Professor Daniel A. Keating – solid scholarship concerning deification and patristics

I first became cognizant of Dr. Keating with the publication of his book, Deification and Grace in 2007 (link). This contribution is one the best introductions to the doctrine of deification I have read. It is one of those rare books that is both concise and comprehensive. [An excellent review is available via THIS LINK - LINK2.]

Dr. Keating’s bibliography referenced an earlier book of his—The Appropriation of Divine Life in Cyril of Alexandria, 2004—that is another must read on the topic of deification (link).

It had been over a decade since I last read anything from Dr. Keating, but that changed when I finally obtained a copy of a book that was on my wish list for months—The Oxford Handbook of Deification, 2024 (link). This work contains 44 essays, and a good number of them provide quotes from Dr. Keating’s two books referenced above, as well as some of his articles that I was not aware of.

This led to some online research during which I discovered a website I had never seen before—Encyclopedia of Catholic Theology (link). On March 12, 2025, an article on Deification by Dr. Keating was published on the site that can be read online and downloaded as a PDF (link). As much as I appreciated and enjoyed his book on deification, I must say that this article is probably a better introduction to the doctrine of deification for those folk who have not read much on the topic—it is also a great refresher for those have.

Looking to learn what other folk think about Dr. Keating’s new contribution.

 

Grace and peace,

David

Irenaeus, Bishop of Lugdunum (Lyon) – an enigmatic passage from his Proof of the Apostolic Preaching

Over this last weekend, I spent a number of hours comparing the four English translations I have of Irenaeus’ Demonstration/Proof of the Apostolic Preaching. One particular passage made an impression on me, that no previous reading had done. The following are the four English translations of that passage [the bold emphasis concerns the portion of passage that caught my eye]:

11. Now, by His hand He created man taking the purest and finest particles from the earth, mixing a determined portion of His power with the dust. Moreover He gave His image to the creature that even what is visible might have the divine form, because the created man was placed upon the earth as one having the divine image and that he might be living, he breathed in his face the breath of life that, both by this breathing and by this creation, man might be like God. (Bishop Karapet and S. G. Wilson, Patrologia Orientalis, vol. 12, 1907, p. 667 - link to pdf)

11. But man He formed with His own hands, taking from the earth that which was, purest and finest, and mingling in measure His own power with the earth. For He traced His own form on the formation, that that which should be seen should be of divine form : for (as) the image of God was man formed and set on the earth. And that he might become living, He breathed on his face the breath of life ; that both for the breath and for the formation man should be like unto God. (J. Armitage Robinson, St. Irenaeus -  The Demonstration of the Apostolic Preaching, 1920, p. 80 - link to pdf)

11. But man He fashioned with His own hands, taking of the purest and finest of earth, in measured wise mingling with the earth His own power; for He gave his frame the outline of His own form, that the visible appearance too should be godlike — for it was as an image of God that man was fashioned and set on earth — and that he might come to life, He breathed into his face the breath of life, so that the man became like God in inspiration as well as in frame. (Joseph P. Smith, S.J., St. Irenaeus - Proof of the Apostolic Preaching, 1952, p. 54 - link to pdf)

11. But He fashioned (πλάσσω) man with His own Hands, taking the purest, the finest <and the most delicate> [elements] of the earth, mixing (συγκράννυμι) with the earth, in due measure, His own power (δύναμις); and because He <sketched upon> the handiwork (πλάσμα) His own form—in order that what would be seen should be godlike (θεοειδής), for man was placed on the earth fashioned <in> the image (εἰκών) of God—and that he might be alive, "He breathed into His face a breath of life": so that both according to the inspiration and according to the formation, man was like (ὃμοιος) God. (Fr. John Behr, St. Irenaeus - On the Apostolic Preaching, 1997 pp. 46, 47 - link to Google Books preview)

A question that immediately came to mind is, what did Irenaeus mean by “His [God] own form”?

An interesting answer to my question has been provided by Joseph P. Smith in his note on the passage:

"He gave his frame the outline of His own form, that the visible appearance too should be godlike": stelcuacin ziwrsn paragreac jews, zi ew or tesanic'inn Astuacajew ice, more literally "for the formation He outlined His own form, that also what would be seen should be deiform"; there can be no doubt that Irenaeus is here teaching man's bodily resemblance to God. (pp. 148, 149)

Man’s bodily resemblance to God? I would like to hear from folk who take the time to read is post—is Smith correct, or are there better interpretations?

Grace and peace,

David

“Partakers of the Divine Nature”: some expositions on the doctrine of deification from an unlikely source

Before delving into the primary theme of this post—i.e. the ‘unlikely source’—I would like to provide an introduction of sorts on the doctrine of deification (also termed theosis). From the entry under the heading “Deification” in The Westminster Dictionary of Christian Theology (1983) we read:

Deification (Greek theosis) is for Orthodoxy the goal of every Christian. Man, according to the Bible, is ‘made in the image and likeness of God’ (cf. Gen. 1.26), and the Fathers commonly distinguish between these two words. The image refers to man’s reason and freedom, that which distinguishes him from the animals and makes him kin to God, while ‘likeness’ refers to 'assimilation to God through virtues' (St John Damascus). It is possible for man to become like God, to become deified, to become god by grace. This doctrine is based on many passages of both OT and NT (e.g. Ps. 82 (81).6; 2 Peter 1.4), and it is essentially the teaching both of St Paul, though he tends to use the language of filial adoption (cf. Rom. 8.9-17; Gal. 4.5-7), and the Fourth Gospel (cf. 17.21-23). [Page 147 - for more Biblical passages germane to this issue see THIS POST.]

The Catechism of the Catholic Church under Part One 'The Profession of the Christian Faith’, chapter two, article 3.I.460 ‘Why did the Word become flesh?’, had the following to say:

The Word became flesh to make us "partakers of the divine nature":78 "For this is why the Word became man, and the Son of God became the Son of man: so that man, by entering into communion with the Word and thus receiving divine sonship, might become a son of God."79 "For the Son of God became man so that we might become God."80 "The only-begotten Son of God, wanting to make us sharers in his divinity, assumed our nature, so that he, made man, might make men gods."81.

78 2 Pt 1:4.

79 St. Irenaeus, Adv. haeres. 3, 19, 1: PG 7/1, 939.

80 St. Athanasius, De inc. 54, 3: PG 25, 192B.

81 St. Thomas Aquinas, Opusc. 57, 1-4.

[Libreria Editrice Vaticana, Eng. 1994 ed. p. 116; Eng. 1997 2^nd ed. p. 116 - for additional selections on deification from Catholic authors see THIS THREAD; for dozens of references from the Church Fathers see THIS POST.]

Robert V. Rakestraw provides an Evangelical perspective on deification; note the following:

In one of his letters Athanasius, the fourth-century defender of the faith, made his famous statement that the Son of God became man “that he might deify us in himself.”1 Elsewhere he wrote similarly that Christ “was made man that we might be made God.”2 This is the doctrine of theosis, also known as deifcation, divinization or, as some prefer, participation in God.3

While the concept of theosis has roots in the ante-Nicene period, it is not an antiquated historical curiosity. The idea of divinization, of redeemed human nature somehow participating in the very life of God, is found to a surprising extent throughout Christian history, although it is practically unknown to the majority of Christians (and even many theologians) in the west.

1 Athanasius, Letter 60, to Adelphius, 4. See also 3, 8 (NPNF, 2d Series 4.575–578).

2 Athanasius On the Incarnation 54 (NPNF, 2d Series 4.65).

3 A. M. Allchin entitles his book on theosis Participation in God: A Forgotten Strand in Anglican Tradition (Wilton: Morehouse-Barlow, 1988).["Becoming Like God: An Evangelical Doctrine of Theosis", JETS 40/2 (June 1997) 257-269 – LINK.]

Time now to introduce the ‘unlikely source’ mentioned in the title of this thread: Charles Taze Russell. Russell was the founder of the Zion's Watch Tower Tract Society of Pennsylvania (1881; incorporated 1884), the related magazine Zion's Watch Tower and Herald of Christ's Presence (1879), and the movement that became known as the Jehovah’s Witnesses (the name adopted in 1931). From the first three volumes of his six volume magnum opus, Millennial Dawn (later renamed Studies in the Scriptures), we read (all bold emphasis that follows in mine):

If the masses of mankind are saved from all the degradation, weakness, pain, misery and death which result from sin, and are restored to the condition of human perfection enjoyed before the fall, they are as really and completely saved from that fall as those who, under the special “highcalling” of the Gospel age, become “partakers of the divine nature." (Millennial Dawn, 1.173)

Notice that this teaches not only that angelic nature is not the only order of spirit being, but that it is a lower nature than that of our Lord before he became a man ; and he was not then so high as he is now, for “God hath highly exalted him,” because of his obedience in becoming man’s willing ransom. (Phil. 2 : 8, 9.) He is now of the highest order of spirit being, a partaker of the divine (Jehovah’s) nature. (Millennial Dawn, 1.178)

When Jesus was in the flesh he was a perfect human being ; previous to that time he was a perfect spiritual being ; and since his resurrection he is a perfect spiritual being of the highest or divine order. It was not until the time of his consecration even unto death, as typified in his baptism—at thirty years of age (manhood, according to the Law, and therefore the right time to consecrate himself as a man)—that he received the earnest of his inheritance of the divine nature. (Matt. 3 : 16, 17.) Tlie human nature had to be consecrated to death before he could receive even the pledge of the divine nature. And not until that consecration was actually carried out and he had a6lually sacrificed the human nature, even unto death, did our Lord Jesus become a full partaker of the divine nature. After becoming a man he became obedient unto death ; wherefore, God hath highly exalted him to the divine nature. (Phil. 2 : 8, 9.) If this Scripture is true, it follows that he was not exalted to the divine nature until the human nature was actually sacrificed—dead. (Millennial Dawn, 1.179)

…it is purely of God's favor that angels are by nature a little higher than men ; and it is also of God's favor that the Lord Jesus and his bride become partakers of the divine nature. It becomes all his intelligent creatures, therefore, to receive with gratitude whatever God bestows. Any other spirit justly merits condemnation, and, if indulged, will end in abasement and destruction. A man has no right to aspire to be an angel, never having been invited to that position ; nor has an angel any right to aspire to the divine nature, that never having been offered to him. (Millennial Dawn, 1.189)

None have a right to dictate to God. If he established the earth, and if he formed it not in vain, but made it to be inhabited by restored, perfect men, who are we that we should reply against God, and say that it is unjust not to change their nature and make them all partakers of a spiritual nature either like unto the angels, or like unto his own divine nature ? (Millennial Dawn, 1.191)

That the Christian Church, the body of Christ, is an exception to God's  general plan for mankind, is evident from the statement that its selection was determined in the divine plan before the foundation of the world (Eph. 1 : 4, 5), at which time God not only foresaw the fall of the race into sin, but also predetermined the justification, the santification and the glorification of this class, which, during the Gospel age, he has been calling out of the world to be conformed to the image of his Son, to be partakers of the divine nature and to be fellow-heirs with Christ Jesus of the Millennial Kingdom for the establishment of universal righteousness and peace.—Rom. 8 : 28-31. (Millennial Dawn, 1.193)

The conditions on which the Church may be exalted with her Lord to the divine nature (2 Pet. 1 : 4) are precisely the same as the conditions on which he received it ; even by following in his footprints (1 Pet. 2 : 21), presenting herself a living sacrifice, as he did, and then faithfully carrying out that consecration vow until the sacrifice terminates in death. This change of nature from human to divine is given as a reward to those who, within the Gospel age, sacrifice the human nature, as did our Lord, with all its interests, hopes and aims, present and future—even unto death. In the resurrection such will awake, not to share with the rest of mankind in the blessed restitution to human perfection and all its accompanying blessings, but to share the likeness and glory and joy of the Lord, as partakers with him of the divine nature.—Rom 8:17; 2 Tim. 2:12. (Millennial Dawn, 1.196)

Those thus transformed, or in processor change, are reckoned “new creatures,” begotten of God, and partakers to that extent of the divine nature. Mark well the difference between these “new creatures” and those believers and “brethren” who are only justified. Those of the latter class are still of the earth, earthy, and, aside from sinful desires, their hopes, ambitions and aims are such as will be fully gratified in the promised restitution of all things. But those of the former class are not of this world, even as Christ is not of this world, and their hopes center in the things unseen, where Christ sitteth at the right hand of God. The prospect of earthly glory, so enchanting to the natural man, would no longer be a satisfying portion to those begotten of this heavenly hope, to those who see the glories of the heavenly promises, and who appreciate the part assigned them in the divine plan. This new, divine mind is the earnest of our inheritance of the complete divine nature—mind and body. Some may be a little startled by this expression, a divine body; but we are told that Jesus is now the express image of his Father's person, and that the overcomers will “be like him and see him as he is.” (1 John 3:2.) “There is a natural [human] body, and there is a spiritual body.” (1 Cor. 15 : 44.) We could not imagine either our divine Father or our Lord Jesus as merely great minds without bodies. Theirs are glorious spiritual bodies, though it doth not yet appear how great is the glory, and it shall not, until we also shall share the divine nature. (Millennial Dawn, 1.200)

At his second advent he does not come to be subject to the powers that be, to pay tribute to Csesar and to suffer humiliation, injustice and violence; but he comes to reign, exercising all power in heaven and in earth. He does not come in the body of his humiliation, a human body, which he took for the suffering of death, inferior to his former glorious body (Heb. 2:9); but in his glorious spiritual body, which is “the express image of the Father's person” (Heb. 1 13); for, because of his obedience even unto death, he is now highly exalted to the divine nature and likeness, and given a name above every name—the Father’s name only excepted. (Phil. 2:9; 1 Cor. 15:27.) The Apostle shows that it "doth not yet appear" to our human understanding what he is now like; hence we know not what we shall be like when made like him, but we (the Church) may rejoice in the assurance that we shall one day be with him, and like him, and see him as he is (1 John 3 : 2)—not as he was at his first advent in humiliation, when he had laid aside his former glory and for our sakes had become poor, that we through his poverty might be made rich. (Millennial Dawn, 2.108, 109)

[Our Lord was put to death a fleshly or human being, but was raised from the dead a spirit being. And since the Church is to be  “changed” in order that she may be like Christ, it is evident that the change which occurred in the Head was of a kind similar to that described as in reservation for the overcomers, who shall be changed from human to spiritual nature, and made like him—“partakers of the-divine nature.” – footnote p. 108]

…we recognize A. D. 1881 as marking the close of the special favor to Gentiles—the close of the “high calling, “ or invitation to the blessings peculiar to this age—to become joint-heirs with Christ and partakers of the divine nature. And, as we have seen, this marks a great movement among the Jewish people toward Christianity, known as the "Kishenev Movement." (Millennial Dawn, 2.235)

The stopping of the favor or ''call" here, in 1881, is followed, or rather lapped upon, by the general call of the whole world to the Millennial blessings and favors upon condition of righteousness, obedience (not self-sacrifice). This however is a lower call, a lesser favor than that which ceased—a call to enjoy the blessings of the Kingdom, but not to be parts of the anointed, Kingdom class. And this change—this stopping of the higher favor and beginning of a lesser favor—will be little noticed here, now, by reason of the fact that the great prize of the Kingdom and jointheirship with Christ as partakers of the divine nature, has been generally lost sight of in the Church. (Millennial Dawn, 3.218)

So, during the Gospel age, our Lord has continually, through his mouth-pieces in the church, invited all believers to enter into his service. The full reward, the divine nature and kingdom glory, was clearly stated at first, and continually repeated, though not always clearly understood throughout the age. (Millennial Dawn, 3.223, 224)*

 And from Zion’s Watchtower:

"YE ARE GODS."

"I have said ye are Gods; and all of you are children of the Most High. But ye shall die like men, and fall like one of the princes" [literally heads]. Psa. 82:6.

Our high calling is so great, so much above the comprehension of men, that they feel that we are guilty of blasphemy when we speak of being "new creatures"—not any longer human, but "partakers of the divine nature." When we claim on the scriptural warrant, that we are begotten of a divine nature and that Jehovah is thus our father, it is claiming that we are divine beings—hence all such are Gods. Thus we have a family of Gods, Jehovah being our father, and all his sons being brethren and joint-heirs: Jesus being the chief, or first-born. (Zion's Watchtower - December 1881 pp. 2, 3 - Reprints p. 301.)

Many more examples could be added, but I shall end here for now.

Grace and peace,

David

*All six volumes of the Millennial Dawn/Studies in the Scriptures series can be read and/or downloaded via THIS LINK.

Mormonism and Margaret Barker - Part 5

Four of my earliest posts here at AF (11/07 thru 01/08) were part of a series titled: Mormonism and Margaret Barker. This post will be the fifth installment of this series.

Yesterday, I received in the mail volume 56.1 (2017) of the BYU Studies Quarterly journal (see this link for full content). This issue included, "a lightly edited transcript of a lecture delivered by Old Testament scholar Margaret Barker at Brigham Young University on November 9, 2016" (p. 75).

Barker's contribution was titled, "The Lord Is One", which is an interesting one, given the primary content of the lecture—deification/theosis in the Bible. This topic of deification/theosis in the Bible is a common theme in a number of Barker's articles, books, and lectures. In part 3 (link) of my aforementioned series, I contrast some of Barker's reflections on deification/theosis with those within the Mormon paradigm. I concluded that post with:

A careful analysis of Barker’s teachings on first Temple deification offers little (if any) resemblance to deification/exaltation in LDS theology. Not only does deification take place prior to ones death and entrance into heaven, deification has nothing to do with the resurrection of the physical body; which is a non-negotiable element of Latter-day Saint deification/exaltation.

The edited transcript of Barker's 11/09/16 lecture presents no new material that would give me cause to change any of my previous assessments contained in the first four installments of this series. Though Barker's contributions are always an interesting read (IMO), her unwavering commitment to a number of liberal presuppositions and theories advanced by critics and skeptics of the Bible makes it extremely difficult for me to embrace, and/or endorse, the general thrust of a number of the conclusions she has reached—e.g. Yahweh is not the one true God of Israel, the "Deuteronomists" changed and corrupted the original teachings of the "First Temple Theology", the king of Israel was "the Lord in human form", et al. (See Barker's website for a listing of all of her contributions; a good number of her published papers are available there for free.)

One glaring flaw contained in the edited transcript is her belief that the, "Deuteronomists also denied the ancient belief that the Lord was seen in human form, what the Christians would later call incarnation" (p. 82). She appeals to Deut. 4:12 to support this belief, stating:

The Deuteronomists, however, said that no divine form was seen, even when Moses received the Ten Commandments: “The Lord spoke to you out of the midst of the fire; you heard the sound of words but saw no form; there was only a voice” (Deut. 4:12). (Page 82)

Barker is unable (unwilling?) to harmonize Deut. 4:12 with those numerous verses contained in the Bible which state that God was "seen". Why is it that she cannot accomplish what so many other scholars/theologians have done? I cannot help but think that her liberal presuppositions and theories are at play here.

Complicating Barker's assessment is her enlisting of a number of verses from the Gospel of John which she believes contradicts Deut. 4:12, and the so-called teaching of the Deuteronomists. And yet, it is from the writings of John that one finds the strongest statements that God has not been seen, nor can be seen! (See my previous thread for germane references.)

Anyway, I wanted to bring to the attention of my readers this latest contribution by Barker. I am confident that my future posts concerning the visio Dei or vision of God will expose certain weaknesses in Barker's assessments, and also demonstrate that the verses she finds so contradictory are in fact harmonious.

Grace and peace,

David

Catholics on deification

Earlier today, in the combox of a recent thread here at AF, an astute reader wrote:

So I think maybe the whole realm of "how does one get saved", hasn't been quite fleshed out properly as the 1st centuries were so focussed on getting Christology right, maybe some of the implications of Jesus' taking up human nature, wasn't thought out fully. This can be seen in that the East & West have diverged on: vicarious atonement vs theosis & divinization and what that means in practise. (LINK)

There is no question that the EO churches have placed a much greater emphasis on the doctrine of "theosis & divinization" (i.e. deification) than the churches within the Latin/Western tradition. However, with that said, there have been a number of Catholic theologians who have embraced the concept of deification. In doing so, they follow a rich tradition found throughout the writings of the Church Fathers (see THIS THREAD). In two prior posts (first; second), I have touched on deification within the Catholic tradition. The following selections will bring to the fore a number of other Catholics who have written on the doctrine:

G. H. Joyce

God, says St. Peter “has given us most great and precious promises that by these you may be made partarkers of the Divine nature (2 Pet. i. 4). Startling as the words are, the teaching which we have already considered will have prepared us for them. They signify that the sonship conferred on us through Jesus Christ raises us so far above our creaturely condition, that by it we partake in the life which is proper to the Three Divine Persons in virtue of Their nature. The passage does not stand altogether alone. When our Lord prays to His Father on behalf of the apostles and all who through their word should believe in Him, “that they all many be one, as Thou, Father in Me and I in Thee, that they may be made perfect in one” (John xvii. 22, 23), His words can hardly signify less than this. If our union with God is comparable to that which unites the Father and the Son, it can only be a union bases on a share in the Divine life...The fathers of the Church from the earliest times with one consent take the apostle’s words in their literal sense. There is no question of any figurative interpretation. They do not hesitate to speak of the “deification” of man. By grace, they tell us, men become gods. (G.H. Joyce, S.J., The Catholic Doctrine of Grace, London: 1920,  pp. 34, 35)

Matthias Joseph Scheeben

If man is to be reunited to God as his Father, God Himself must raise him up again to His side...God must again draw man up to His bosom as His child, regenerate him to new divine life, and again clothe him with the garment of His children, the splendor of His own nature and glory...this transformation of the will is essentially bound up with the inner elevation of our entire being by the grace of divine sonship and participation in the divine nature...The children of God participate as such in the divine holiness of their Father, in His very nature. (Matthis J. Scheeben, The Mysteries of Christianity, B. Herder Book Co.: St. Loius, pp. 615, 616, 617, 619 - emphasis mine - German first ed. 1865; English ed. 1946, translated from the 1941 German ed.)

What we cannot claim by right, the infinite liberality of God gives us in grace. Although we are not by nature the children of God, we become such through grace, and so true is this that, as adopted children, we are put on par with the natural Son of God. We become by grace what He is by nature. What He has in Himself, that we obtain through participation in His nature. (Matthis J. Scheeben, The Glories of Divine Grace, Tan Books, 2000, p. 96.)

“But the Son is not only kindred or similar to the Father, He is one with Him as the branch is one with the tree, the ray of light with the light, the brook with the fountain. So too, grace makes us one with God, not in the same perfect manner [i.e. ‘by nature’], but in a similar way. And yet it is not a question of a mere relationship or similarity, but on an intimate union which makes us, as it were, one being with God” (Ibid., p. 154).

“Thus, when we are united to God by grace [i.e. not ‘by nature’, as is the Son], we not only obtain and direct into our soul a ray of divine glory, a small stream of divine life, but we may also consider as our own the divine Sun itself, the foundation of divine life, and we may rejoice at God’s perfections as though they were ours” (Ibid., p. 158).  

Fr. Reginald Garrigou-Lagrange, O.P

 …we must bear in mind that grace is really and formally a participation in the divine nature precisely in so far as it is divine, a participation in the Deity, in that which makes God God, in His intimate Life…Grace is a mysterious participation in this essence, which surpasses all natural knowledge…Grace makes us participate really and formally in this Deity, in this eminent and intimate life of God, because grace is in us the radical principle of essentially divine operating that will ultimately consist in seeing God immediately, as He sees Himself, and in loving Him as He loves Himself. Grace is the seed of glory. In order to know its essence intimately, we must first have seen the divine essence of which grace is the participation. (Fr. Reginald Garrigou-Lagrange, O.P., Christian Perfection and Contemplation, St. Louis and London: B. Herder Book Co., 1937 – reprinted by Tan Books and Publishers, 2003, pp. 55, 56.)

The Deity as we know it here on earth contains only implicitly the divine attributes deduced from it. But when we shall see it as it is in itself there will no longer be any need for deduction. We shall see explicitly in the eminence of the Deity, superior to being, to unity, to goodness, all the infinite perfections and the three divine persons. (Fr. Reginald Garrigou-Lagrange, O.P., Our Saviour and His Love For Us, St. Louis and London: B. Herder Book Co., 1951 – reprinted by Tan Books and Publishers, 1998, pp. 351, 352.)

Lugwig Ott

The Church prays in the Offertory of the Holy Mass : “Grant that by the mystery of this water and wine, we may be made partakers of His divinity, who vouchsafed to become partaker of our humanity.” Similarly in the Preface of the Feast of Christ’s Ascension into Heaven : “He was assumed into Heaven in order that we might be partakers in His divinity.” Cf. D 1021.

According to 2 Peter 1, 4 the Christian is elevated to participation in the Divine nature...Again, the scriptural texts which represent justification as generation or birth from God  (John 1, 12 et seq. ; 3, 5 ; 1 John 3, 1. 9 ; Tit. 3. 5 ; James 1, 18 ; 1 Peter 1, 23), indirectly teach the participation of man in the Divine nature, as generation consists in the communication of the nature of the generator to the generated.

From the scriptural texts cited, and from others (Ps. 81, 1. 6 ; John 10, 34 et seq.), the Fathers derived the teaching of the deification of man by grace (θείωσις, deificatio). It is a firm conviction of the Fathers that God became man so that man might become God, that is, defied. (Dr. Lugwig Ott, Fundamentals of Catholic Dogma, p. 256 - German ed. 1952; English 1955.)

George D. Smith

The application of all this to the question of sanctifying grace will be seen more and more as we proceed, but for the present we simply assert the magnificent truth that grace is not only a positive reality in the soul, not only a reality which no created being could produce, but a reality which in itself is higher than the whole order of created things (even angelic) and is truly divine. This brings us at once to a wonderful phrase of St Peter, who says that we are made “partakers of the divine nature.” Catholic theology has ever clung to the belief that here we have no mere figure of speech but the declaration of a definite fact. We really are made to be partakers of the divine nature. It is not merely that our spiritual faculties of intellect and will establish a special likeness to God in our souls; that is true enough, but over and above this natural likeness to God a wholly supernatural quality is given to us which makes us to be of the same nature as God...St Augustine puts the matter thus: He descended that we might ascend, and “whilst retaining his own divine nature he partook of our human nature, that we whilst keeping our own nature, might become partakers of his.” St Thomas Aquinas, echoing the constant teaching of the past, declares in a passage which the Church uses for the feast of Corpus Christi: “the only-begotten Son of God, wishing to make us partakers of his own divinity, took upon himself our human nature that having become man he might make men to be gods.” And we know how the Church has enshrined this wonderful truth in one of the most beautiful of the prayers at Mass. “O God, who in creating human nature, didst marvellously ennoble it, and hast still more marvellously renewed it, grant that by the mysery of this water and wine we may be made partakers of his Godhead, who vouchsafed to become partaker of our humanity, Jesus Christ, thy Son, our Lord.” (The Teaching of the Catholic Church, edited by Canon George D. Smith, 1960, volume 1, pp. 553, 554.)

Both St John and St Paul exult in proclaiming this act of divine condescension. “Dearly beloved,” the first writes with all the earnestness of the disciple of love, “we are now the sons of God: and it hath not yet appeared what we shall be. We know that when he shall appear we shall be like to him: because we shall see him as he is. And everyone that hath this hope in him sanctifieth himself.”...In light of such luminous teaching it is clear that is in a very special sense that we are children of God...Sanctifying grace, as we have seen, is a positive reality infused into the soul by which we are made to share the divine life...By sanctifying grace the very life of God is imparted unto them. (Ibid. pp. 556, 557.)

Catherine Mowry LaCugna

Jesus Christ, the visible icon of the invisible God, discloses what it means to be fully personal, divine as well as human. The Spirit of God, poured into our hearts as love, (Rom. 5:5), gathers us together into the body of Christ, transforming us so that “we become by grace what God is by nature,” namely, persons in full communion with God and with every creature. (God For Us, p. 1.)

Saint Joseph Daily Missal

Deus, qui humanae substantiae dignitatem mirabiliter condidisti, et mirabilius reformasti: da nobis per hujus aquae et vini mysterium, ejus divinitatis esse consortes, qui humanitatis nostrae fieri dignatus est particeps, Jesus Christus Filius tuus Dominus noster: Qui tecum vivit et regnat in unitate Spiritus Sancti Deus. per omnia saecula saeculorum. Amen.

O GOD, Who established the nature of man in wondrous dignity, and still more admirably restored it, grant that through the mystery of this water and wine, we may be made partakers of His Divinity, who has condescended to become partaker of our humanity, Jesus Christ, Your Son, our Lord: Who with You lives and reigns in the unity of the Holy Spirit, God, world without end. Amen. (Saint Joseph Daily Missal, 1961, pp. 660, 661.)

John Paul II

This is the central truth of all Christian soteriology that finds an organic unity with the revealed reality of the God-Man. God became man that man could truly participate in the life of God—so that, indeed, in a certain sense, he could become God. The Fathers of the Church had a clear consciousness of this fact. It is sufficient to recall St. Irenaeus who, in his exhortations to imitate Christ, the only sure teacher, declared: “Through the immense love he bore, he became what we are, thereby affording us the opportunity of becoming what he is.” (John Paul II, Jesus, Son and Savior, 1996, p. 215 - General audience address September 2, 1987.)

John Paul II – Dominum et Vivificantem Thus there is a supernatural “adoption,” of which the source is the Holy Spirit, love and gift. As such he is given to man. And in the superabundance of the uncreated gift there begins in the heart of all human beings that particular created gift whereby they “become partakers of the divine nature.” Thus human life becomes permeated, through participation, by the divine life, and itself acquires a divine, supernatural dimension. (The Encyclicals of John Paul II, p. 318.)

John Paul II - Redemptor Hominis The Church has only one life: that which is given her by her Spouse and Lord. Indeed, precisely because Christ united himself with her in his mystery of Redemption, the Church must be strongly united with each man. This union of Christ with man is in itself a mystery. From the mystery is born “the new man,” called to become a partaker of God’s life. (The Encyclicals of John Paul II, p. 79.)

Second Vatican Council

For Jesus Christ was sent into the world as the true Mediator between God and men. Since He is God, all the fullness of the divine nature dwells in Him bodily (Col. 2:9); as man he is the new Adam, full of grace and of truth (John 1:14) , who has been constituted head of a restored humanity. So the Son of God entered the world by means of a true incarnation that he might make men sharers in the divine nature; though rich, he became poor for our sake, that by his poverty we might become rich (2 Cor. 8:9). (Ad Gentes Divinitus, from Vatican Council II - The Conciliar and Post Conciliar Documents, General Editor, Austin Flannery, O. P., New Revised Edition 1992, p. 815.)

The New Catechism

The Word became flesh to make us “partakers of the divine nature”: “For this is why the Word became man, and the Son of God became the Son of man: so that man, by entering into communion with the Word and thus receiving divine sonship, might become a son of God.” “For the Son of God became man so that we might become God.” “The only-begotten Son of God, wanting to make us sharers in his divinity, assumed our nature, so that he, made man, might make men gods.” (Catechism of the Catholic Church, 1994 edition, p. 116.)

Catechism of the Catholic Church

[The following quotes are from the Catechism of the Catholic Church, provided via the official Vatican website: link.]

460 The Word became flesh to make us "partakers of the divine nature":⁷⁸ "For this is why the Word became man, and the Son of God became the Son of man: so that man, by entering into communion with the Word and thus receiving divine sonship, might become a son of God."⁷⁹ "For the Son of God became man so that we might become God."⁸⁰ "The only-begotten Son of God, wanting to make us sharers in his divinity, assumed our nature, so that he, made man, might make men gods."⁸¹

[Footnotes: #78 – 2 Pet 1:4;  #79 – St. Irenaeus, Adv. haeres. 3,19,1: PG 7/1, 939; #80 – St. Athanasius, De inc., 54,3: PG 25, 192B; #81 – St. Thomas Aquinas, Opusc. 57: 1-4 ]

1023 Those who die in God's grace and friendship and are perfectly purified live for ever with Christ. They are like God for ever, for they "see him as he is," face to face:⁵⁹⁶

By virtue of our apostolic authority, we define the following: According to the general disposition of God, the souls of all the saints . . . and other faithful who died after receiving Christ's holy Baptism (provided they were not in need of purification when they died, . . . or, if they then did need or will need some purification, when they have been purified after death, . . .) already before they take up their bodies again and before the general judgment - and this since the Ascension of our Lord and Savior Jesus Christ into heaven - have been, are and will be in heaven, in the heavenly Kingdom and celestial paradise with Christ, joined to the company of the holy angels. Since the Passion and death of our Lord Jesus Christ, these souls have seen and do see the divine essence with an intuitive vision, and even face to face, without the mediation of any creature.⁵⁹⁷

[Footnote #597 – Benedict XII, Benedictus Deus (1336): DS 1000: cf. LG 49]

1721 God put us in the world to know, to love, and to serve him, and so to come to paradise. Beatitude makes us "partakers of the divine nature" and of eternal life.²¹ With beatitude, man enters into the glory of Christ²² and into the joy of the Trinitarian life.

[Footnotes: #21 – 2 Pet 1:4; Jn 17:3; #22 – Cf. Rom 8:18 ]

1726 The Beatitudes teach us the final end to which God calls us: the Kingdom, the vision of God, participation in the divine nature, eternal life, filiation, rest in God.

1812 The human virtues are rooted in the theological virtues, which adapt man's faculties for participation in the divine nature:⁷⁶ for the theological virtues relate directly to God. They dispose Christians to live in a relationship with the Holy Trinity. They have the One and Triune God for their origin, motive, and object.

[Footnote #76 – 2 Pet 1:14 ]

1988 Through the power of the Holy Spirit we take part in Christ's Passion by dying to sin, and in his Resurrection by being born to a new life; we are members of his Body which is the Church, branches grafted onto the vine which is himself:³⁶ 

[God] gave himself to us through his Spirit. By the participation of the Spirit, we become communicants in the divine nature. . . . For this reason, those in whom the Spirit dwells are divinized.³⁷

[Footnotes: #36 – Cf. 1 Cor 12; Jn 15:1-4; #37 – St. Athanasius, Ep. Serap. 1,24: PG 26, 585 and 588 ]

1999 The grace of Christ is the gratuitous gift that God makes to us of his own life, infused by the Holy Spirit into our soul to heal it of sin and to sanctify it. It is the sanctifying or deifying grace received in Baptism. It is in us the source of the work of sanctification:⁴⁸

[Footnote #48 – Cf. Jn 4:14; 7:38-39 ]

And lastly, I must mention a recent book of collected essays by Catholic authors concerning the doctrine of deification:

Called To Be Children of God

Grace and peace,

David