I have been reading and studying Augustine of Hippo, off and on, for over 30 years now. I have amassed well over 100 volumes of books either by or about him, and my digital collection easily doubles that figure in pdf versions—add the dozens of scholarly articles and essays I have diligently collected (paper, pdf and html)—I guess it is safe to say that my personal collection is fairly substantive. However, with that said, I sometimes feel I have only 'scratched the surface' when it comes to Augustine; just when I think I have gained a good grasp of his thought, a fresh reading of him, and/or some scholar's treatment, sends me back to the 'drawing board' (so to speak)—the last couple of days have sent me, yet once again, "back to the 'drawing board'", and it began with a renewed reading of De symbolo ad catechumenos (On The Creed) and De fide et symbolo (On Faith and the Creed). This prompted me to reread Michel René Barnes', "Rereading Augustine's Theology of the Trinity" (in, The Trinity, edited by Davis, Kendall, and O'Collins - 1999), and Lewis Ayres' chapter on Augustine in his, Nicaea and its Legacy (2004), leading to some online research, during which I dug up the following two essays that were new to me:
But, I am getting ahead of myself; I need to back-up a bit, and share some selections from On The Creed and On Faith and the Creed, which should set the tone for the essays by Barnes and Kuehn. I will be using the English translations provided by Cornish and Salmond in the 3rd volume of A Select Library of the Nicene and Post-Nicene Fathers (Schaff) [pdf copy: HERE; Latin texts available online: HERE]. Keeping in mind the distinction between the Latin/Western and Greek/Eastern approaches to the doctrine of the Trinity drawn by a number of patristic and theological scholars of the last few decades, one will find that the following selections are more in line with the Greek/Eastern approach. After his commentary on the Creed's "I believe in God , the Father Almighty", Augustine then continues with:
For this reason we believe also in His Son, that is to say, God the Father Almighty's, "His Only Son, our Lord." When thou hearest of the Only Son of God, acknowledge Him God. For it could not be that God's Only Son should not be God. What He is, the same did He beget, though He is not that Person Whom He begot. If He be truly Son, He is that which the Father is; if He be not that which the Father is, He is not truly Son. Observe mortal and earthly creatures: what each is, that it engendereth. Man begets not an ox, sheep begets not dog, nor dog sheep. Whatever it be that begetteth, that which it is, it begetteth. (On The Creed, p. 370)
Augustine's argument is pretty straight forward here—as Man begets Man, God begets God. He then goes on to argue against there being two Gods, utilizing a verse from Sacred Scripture that I had not seen used in this way before:
God gives that when he has believed he soon understands; that is God's gift, not human frailness. Still, if ye do not yet understand, believe: One God the Father, God Christ the Son of God. Both are what? One God. And how are both said to be One God ? How ? Dost thou marvel ? In the Acts of the Apostles, "There" was, "it says, in the believers, one soul and one heart." There were many souls, faith had made them one. So many thousands of souls were there; they loved each other, and many are one: they loved God in the fire of charity, and from being many they are come to the oneness of beauty. If all those many souls the dearness of love made one soul, what must be the dearness of love in God, where is no diversity, but entire equality! If on earth and among men there could be so great charity as of so many souls to make one soul, where Father from Son, Son from Father, hath been ever inseparable, could They both be other than One God ? Only, those souls might be called both many souls and one soul; but God, in Whom is ineffable and highest conjunction, may be called One God, not two Gods. (Ibid. p. 370)
Augustine gets even more "Greek" in his On Faith and the Creed; note the following:
Thus, then, the Son according to nature (naturalis filius) was born of the very substance of the Father, the only one so born, subsisting as that which the Father is, God of God, Light of Light. (On Faith and the Creed, p. 324)
Shortly after showing his "Latin" side by stating that "this Trinity is one God", Augustine then uses physical analogies (as do a number of Greek Church Fathers) to clarify what he means by "one God":
Neither is it strange that these things are said in reference to an ineffable Nature, when even in those objects which we discern with the bodily eyes, and judge of by the bodily sense, something similar holds good. For take the instance of an interrogation on the subject of a fountain, and consider how we are unable then to affirm that the said fountain is itself the river; and how, when we are asked about the river, we are as little able to call it the fountain; and, again, how we are equally unable to designate the draught, which comes of the fountain or the river, either river or fountain. Nevertheless, in the case of this trinity we use the name water [for the whole]; and when the question is put regarding each of these separately, we reply in each several instance that the thing: is water. For if I inquire whether it is water in the fountain, the reply is given that it is water; and if we ask whether it is water in the river, no different response is returned; and in the case of the said draught, no other answer can possibly be made: and yet, for all this, we do not speak of these things as three waters, but as one water. (Ibid. p. 328)
A bit later we read:
But in the case of that Trinity, we have affirmed it to be impossible that the Father should be sometime the Son, and sometime the Holy Spirit: just as, in a tree, the root is nothing else than the root, and the trunk (robur) is nothing else than the trunk, and we cannot call the branches anything else than branches; for, what is called the root cannot be called trunk and branches; and the wood which belongs to the root cannot by any sort of transference be now in the root, and again in the trunk, and yet again in the branches, but only in the root; since this rule of designation stands fast, so that the root is wood, and the trunk is wood, and the branches are wood, while nevertheless it is not three woods that are thus spoken of, but only one [wood]. (Ibid. p. 328)
But these examples in things material (corporalia exetnpla) have been adduced not in virtue of their likeness to that divine Nature, but in reference to the oneness which subsists even in things visible, so that it may be understood to be quite a possibility for three objects of some sort, not only severally, but also all together, to obtain one single name; and that in this way no one may wonder and think it absurd that we should call the Father God, the Son God, the Holy Spirit God, and that nevertheless we should say that there are not three Gods in that Trinity, but one God and one substance. (Ibid. p. 328)
I think for the first time I finally understand why Augustine was so adamant in calling the Trinity "one God"; his above analogies have cleared up some misconceptions I had developed by focusing on a number of negative appraisals that have come from Eastern Orthodox and Protestant authors.
Now, with the above in place and in mind, I shall recommend the reading of the essays by Barnes and Kuehn, and shall patiently wait for the reflections and thoughts from those who have done so.
Grace and peace,