In the history of early Christian theology, few figures exerted greater influence upon a wider range of doctrinal controversies than St. Augustine. Despite the relative marginality and geographical isolation of his see, the doctor gratiae earned a reputation across the Mediterranean, even in his own day, as a leading opponent of the Pelagians. He was likewise a relentless and formidable opponent of Donatism and Manichaeism, and he sealed the victory of pro-Nicene theology among the Latins with his magisterial treatment of the Trinity.

There is, however, one major controversy of the fifth century with which Augustine is not usually associated: the debate about the unity of Christ’s person, the so-called Nestorian controversy, which was reaching fever pitch in the East near the end of Augustine’s life. While it is true that Augustine never wrote a major work on Christology, he in fact had a good deal to say on the subject. His views, which have a clarity and depth that rival those of his Eastern contemporaries, are well worth examining.

Beginning in the mid-fourth century, Greek-speaking theologians in the tradition of Diodore of Tarsus (d. 390) had been working out a Christology that stressed God’s freedom from suffering (or impassibility) and his radical difference from creatures. Diodore argued that it was not God, but a man conjoined to God, who was born of Mary. Similarly, it was not the divine Word who hung upon the cross, who died and was raised, but rather a human being assumed by the Word. The limitations characteristic of creaturely existence, Diodore regularly asserts, are irreconcilable contraries of the transcendence, glory, and freedom of the divine nature. Such limitations must therefore be attributed not to the Word of God himself, but to a human being united to him.

Such thinking went against the grain of some of the deepest theological convictions of Augustine’s mature writings. He consistently and vehemently denied that divine transcendence can be rightly understood in terms of God’s distance from or sheer contrariety to the world. In The City of God 9.12-17, for example, he explains that what separates humanity from God is not creatureliness as such, but sin. The true God, moreover, is distinguished from proud demons precisely by his willingness to descend into the lowliness of mortality and finitude on creation’s behalf. Because there is no inherent incompatibility between the world and its Maker, God displays his nature most brilliantly when he himself becomes creaturely, subjecting himself to our limitations and becoming the Way for our journey home.

Prior to Maximus Confessor in the eighth century, there were arguably very few Greek-speaking theologians making such claims with the same consistency and tenacity as Augustine. Even in Cyril of Alexandria, the textbook champion of orthodox Christology, one rarely finds strong assertions of the natural harmony between the Word of God and the created nature he assumed in the incarnation, such as we encounter with some regularity in Augustine. What made the difference in Augustine’s views, I suggest, is the decidedly Neoplatonist reasons he had for holding them.

In Confessions 7.10.16, Augustine recalls his encounter, while a Milanese professor of rhetoric in the 380’s, with “the books of the Platonists.” These works taught Augustine to reject the logic of competition between God and the world–the logic that made possible not only Manichaean dualism, which is Augustine’s chief preoccupation in Confessions, but also Christologies in the tradition of Diodore (see also Conf. 5.10.20). A fundamental commitment of Neoplatonist metaphysics is that transcendence and difference are not the same thing as remoteness and estrangement. The preservation of God’s incorruptibility and freedom does not depend upon his separation from or natural contrariety to the world. It is indeed because God is utterly beyond any possibility of corruption that he can be present unreservedly to every being, and on every level of being, from the highest to the most inferior. What sets God “apart” from the world is not an inherent incompatibility with its limitations, but rather his unconditional presence in and to all that exists.

While “the Platonists” may not have had a doctrine of the incarnation (Conf. 7.9.13-14), their metaphysics provided vital help to Augustine as he reflected on the Biblical witness to Christ. In his pre-Platonist, Manichaean period, Augustine had rejected the incarnation as pollutive of the divine nature’s purity (Conf. 5.10.20). At that time, he held a Christology even more extreme than Diodore’s, maintaining that Christ was only an inspired man. Even after his conversion, his shift away from this thinking was gradual, as he himself admits (Conf. 7.19.25). Indeed, some have claimed that Augustine did not arrive at a recognizably orthodox view until as late as 395, the year of his ordination as bishop and only a few years before he began composing the Confessions. By the time he came to write The City of God, however, he had spent decades digesting and reformulating the Neoplatonism he had encountered in Milan. We are not surprised, then, to find Augustine now arguing that it is because God is supremely incorruptible and transcendent that he can also humble himself and share in our mortality (City of God 9.12-17). The Most High is recognized by his power to be not only in the heights, but also in the depths; not only exalted and glorified as eternal Word, but also humiliated and crucified as God in the form of a servant. For God’s supreme lordship is grounded in nothing other than his unqualified humility (Conf. 10.36.59).

This insight, and the Scriptural and philosophical reasoning behind it, makes Augustine’s Christology a significant contribution to the development of orthodox theology. It is yet another reason why the church does well to return to Augustine again and again as it seeks to deepen its understanding of the mystery of Christ.