On the Trinity ...
On the Trinity ...

It is a plain matter of fact that none who have depended on the revelation embodied in the Old Testament alone have ever attained to the doctrine of the Trinity. 

If the occasional occurrence of plural verbs and pronouns referring to God, and the plural form of the name 'Elohim, are not insisted upon as in themselves evidence of a multiplicity in the Godhead, yet a certain weight is lent them as witnesses that "the God of revelation is no abstract unity, but the living, true God, who in the fullness of His life embraces the highest variety" (Bavinck).

The upshot of it all is that it is very generally felt that, somehow, in the Old Testament development of the idea of God there is a suggestion that the Deity is not a simple monad.  

"Let us make man in our image, after our likeness.  And God created man in his own image ... " [Genesis 1:26-27] does not encourage us to take the preceding verse as announcing that man was to be created in the image of the angels!

This is not an illegitimate reading of New Testament ideas back into the text John 17:3 1 Corinthians 8:4 1 Timothy 2:5). They do not, then, place two new gods by the side of Yahweh, as alike with Him to be served and worshipped; they conceive Yahweh as Himself at once Father, Son and Spirit. In presenting this one Yahweh as Father, Son and Spirit, they do not even betray any lurking feeling that they are making innovations.

Without apparent misgiving they take over Old Testament passages and apply them to Father, Son and Spirit indifferently. Obviously they understand themselves, and wish to be understood, as setting forth in the Father, Son and Spirit just the one God that the God of the Old Testament revelation is; and they are as far as possible from recognizing any breach between themselves and the Fathers in presenting their enlarged conception of the Divine Being. This may not amount to saying that they saw the doctrine of the Trinity everywhere taught in the Old Testament. It certainly amounts to saying that they saw the Triune God whom they worshipped in the God of the Old Testament revelation, and felt no incongruity in speaking of their Triune God in the terms of the Old Testament revelation. The God of the Old Testament was their God, and their God was a Trinity, and their sense of the identity of the two was so complete that no question as to it was raised in their minds.

Augustine’s work, “On The Trinity,” shaped the direction of thought on the doctrine of God throughout the Middle Ages. His prominence in this area of theology can especially be seen in the western church’s defense of the filioque. There is a sense in which the east’s attack on this doctrine was seen as an attack on Augustine himself. (Pelikan, 21) Aquinas appropriated Augustine’s understanding of the Trinity in his “Summa Theologiae”. In fact, this Augustinian understanding of the Trinity was the key to Aquinas’ whole system of theology. (Pelikan, 279) Bonaventure, writing at the same time as Augustine, further developed the psychological analogies for the Trinity that Augustine himself had developed.  

Bonaventure posited a “trinitarian ontology”, a threeness present in the created order as a reflection of God’s own nature (Pelikan, 283).


Augustine’s writings were used in Hincmar of Reims battle against Gottschalk’s theology of a “trine deity.” Gottschalk seemed to be suggesting that “each person of the Trinity has its own deity and divinity,” which would then avoid the implication that the whole divinity took on flesh in the person of Jesus Christ. To prove this he quoted Augustine, who occasionally used the term “trine deity.” But Hincmar of Reims used Alcuin’s compilation of Augustine’s work on the Trinity to refute this improper reading of the father as well as Gottschalk’s dangerous theology. (Pelikan, 59,61)


Those in Spain who were attempting to revive a form of adoptionism also tried to use Augustine to defend their position, but their opponents used Augustine to defend their own orthodox position. (Pelikan, 65, 66) These debates themselves served to highlight that Augustine’s views, long considered determinative in and of themselves, might indeed need to be explained and given an orthodox interpretation. 

Augustine’s understanding of grace and God’s predestination of the elect was at the center of a number of controversial dialogues in the Medieval period. His strong view of predestination was too much for many theologians, which is why the Synod of Orange in 553 already “tempered” his views. Indeed, on the issue of predestination “what was embarrassing about Augustine was his clarity.” (Pelikan, 81)

Medieval theologians such as Gottschalk found themselves the center of controversy when they adopted pure Augustinian views of predestination. Ratramnus himself, the chief opponent of Radbertus on the issue of the Eucharist, supported Gottschalk in his defense of an Augustinian theology of election. At issue was the tendency for strict Augustinians to adopt a view of atonement as “limited” in some sense to those already predestined by God. The opponents of the Augustinian predestinarians used Augustine’s own views on grace in their support (Pelikan, 82). This debate would continue into the time of the Reformation.

On the issue of the Eucharist, especially in the development of the doctrine of the Real Presence, Augustine was used again by both sides. In fact, the proponents of a figurative or symbolic presence seemed to have Augustine most clearly on their side. Those who were fighting for a literal interpretation of the words of institution realized that “the origin of almost the entire scandal seems to have come from Saint Augustine.” (Pelikan, 218) One statement of Augustine that were most troubling to the supporters of the Real Presence was “Why are you preparing your teeth and your stomach? Believe, and you have already eaten.” (Pelikan, 219) But other statements from Augustine seemed to support the Real Presence. The Eucharist became one area of theology were other western fathers, such as Ambrose, were relied on for proof as much as Augustine (Pelikan, 80).

It was in the development of the doctrine of the atonement that the medieval period went furthest beyond the Augustine synthesis. A proper understanding of Christ’s atonement seemed to be the missing piece that made a more solid doctrine of the Eucharist, of grace, and of predestination possible. Augustine himself had never clearly posited an understanding of Christ’s redemptive work, which seemed to make it possible for others to misunderstand his meaning on those other theological issues. Anselm of Canterbury’s work, Cur Deus Homo, became the definitive book for the later Middle ages on the atonement (Pelikan, 142). In it he showed how only a God-man could satisfy divine justice by being a perfect sacrifice on the part of man to God. This new understanding of Christology and soteriology filled in many blanks left by the synthesis of Augustine’s teaching, making possible a more decisive understanding of the communication of grace, and therefore of the Eucharist and of predestination (Pelikan, 159).

The growing use of reason and natural theology in the later Middle Ages also had its roots in Augustine’s thinking and work. It was Augustine’s use of psychological and natural parallels for the Trinity that spurred other theologians to find God in nature. Bonaventure wrote: “Since every science…is concerned with the Trinity above all else, every science must necessarily present some trace of this same Trinity.” (Pelikan, 282) Thomas Aquinas used Augustine’s relation of nature to grace to support some of his theological methodologies. “Since grace does not abolish nature, but completes it,” he argues, “then natural reason should minister to faith.” (Pelikan, 285)

Augustine, then, did have a profound influence on the thought of theologians in the Middle Ages. His work on predestination opened as many doors as it provided answers. His own thinking on the Trinity not only influenced later clarification of this doctrine, but also paved the way for more work in the area of natural theology. Where Augustine’s doctrines were unclear, later theologians had to continue reconciling his work with that of the other western fathers, some of the eastern fathers, and the Scriptures.

His influence extended to popes and great theologians for over a thousand years. In short, Augustine’s writings shaped the church catholic in the west perhaps as profoundly as any of the apostolic writers.




Pelikan, Jaroslav. The Growth of Medieval Theology. (The University of Chicago Press, Chicago, IL, 1978)

Davis, Donald Leo. The First Seven Ecumenical Councils (325-787). (The Liturgical Press,


15th Century Fresco Showing
the Three Gods in the Holy Trinity