“The following dissertation concerning the Trinity, as the reader ought to be informed, has been written in order to guard against the sophistries of those who disdain to begin with faith, and are deceived by a crude and perverse love of reason.”
Thus begins Augustine in the first line of his magisterial on the Trinity, de Trinitate. It cannot be doubted, then, that this work will be one that is one where faith seeks understanding, and not one where faith comes from understanding. Like Thomas Aquinas centuries later, for Augustine the Trinity is something we can only know through God’s revelation of Himself to us. We can ponder these truths with our God given intellects, both to move towards a knowledge of God and also to refute errors, but we cannot reason our way to a knowledge of the Trinity’s existence as if it can be known from the world of created things.
“Wherefore, our Lord God helping, we will undertake to render, as far as we are able…: that the Trinity is the one and only and true God, how the Father, the Son, and the Holy Spirit are rightly said, believed, understood, to be of one and the same substance or essence.”
Once the plan of the work is stated, St. Augustine moves immediately to Scripture to substantiate the claim that the Father, the Son, and the Holy Spirit are all indeed God, that they are equal, and that they are one. Again, it will not be reason that brings us to a knowledge of the existence of the Trinity, but revelation. Only after it is established can reason do its part in seeking to understand, “our Lord God helping,” something about this Triune God.
“All those Catholic expounders of the divine Scriptures, both Old and New, whom I have been able to read, who have written before me concerning the Trinity, Who is God, have purposed to teach, according to the Scriptures, this doctrine, that the Father, and the Son, and the Holy Spirit intimate a divine unity of one and the same substance in an indivisible equality; and therefore that they are not three Gods, but one God.”
Augustine wishes to follow the lead of these earlier commentators and to learn from the reflections as well: “By supplying them [people who ask questions of the Trinity] with matter to read, I shall profit myself also; and that, in seeking to reply to their inquiries, I shall myself likewise find that for which I was inquiring.”
Augustine is doing his work as a pastor, who, like many holy men, had hoped to live a life of contemplation, but were called by God to serve the Church in a more active way (a very recent example of this is none other than Pope Benedict XVI). At the beginning of Book III, St. Augustine will say so himself: “I would have them believe, who are willing to do so, that I had rather bestow labor in reading, than in dictating what others may read. But let those who will not believe this… grant me whatever answers may be gathered from reading… and then let them see how easily I would refrain from this labor, and with how much even of joy I would give my pen a holiday.”
In chapter 3 of Book I, the Bishop of Hippo lays down a simple rule of interpretation that must be followed when speaking of the Incarnate Christ, who both said “the Father and I are one” but also “the Father is greater than I,” for “men have erred through a want of careful examination or consideration of the whole tenor of the Scriptures, and have endeavored to transfer those things which are said of Jesus Christ according to the flesh, to that substance of His which was eternal before the incarnation, and is eternal.” Therefore, we must discern the difference between what is said of Christ as man, and what is said of Christ as God.
Thomas Aquinas will devote Question 16 of the Third part of the Summa to this in great detail, asking and answering these questions:
- Is this true: “God is man”?
- Is this true: “Man is God”?
- May Christ be called a lordly man?
- May what belongs to the Son of Man be predicated of the Son of God, and conversely?
- May what belongs to the Son of Man be predicated of the Divine nature, and what belongs to the Son of God of the human nature?
- Is this true: “The Son of God was made man”?
- Is this true: “Man became God”?
- Is this true: “Christ is a creature”?
- Is this true: “This man,” pointing out Christ, “began to be”? or “always was”?
- Is this true: “Christ as man is a creature”?
- Is this true: “Christ as man is God”?
- Is this true: “Christ as man is a hypostasis or person”?
The Scriptures indeed tell us the truths of the one Person and two natures in Christ, as well as the one God and three persons of the Trinity, yet a superficial reading by the unlearned, or even a careful reading by the learned, can easily lead to error and to the appearance of contradictions in Scripture. For this reason, St. Augustine has to show early in the work this key principle to reading the Scriptures when it relates to the Incarnate Son of God. Augustine then spends several pages applying this principle to Scripture passages. This comprises the completion of Book I.