The christology of St Gregory the Theologian, writes Christopher Beeley, “remains one of the great theological achievements of Christian tradition” (The Unity of Christ, p. 182). One is struck by how Gregory anticipates the christology of St Cyril of Alexandria. Here is no God dressed in human flesh yet lacking a human consciousness, as in Apollinarius, nor a Jesus distinct from the pre-existent Word, as in Diodore of Tarsus (and later, Nestorius). The Gregorian Christ is Theanthropos, the God-man who lives a full human existence and suffers a horrifying death. In his Third Theological Oration Gregory declares the mystery of the Incarnate Son in all of its paradoxical glory:
He was begotten—yet he was already begotten. … He was carried in the womb, but acknowledged by a prophet as yet unborn himself, who leaped for joy at the presence of the Word for whose sake he had been created. He was wrapped in swaddling bands, but at the Resurrection he unloosed the swaddling bands of the grave. … As man he was baptized, but he absolved sins as God; he needed no purifying rites himself—his purpose was to hallow water. As man he was put to the test, but as God he came through victorious—yes, bids us be of good cheer, because he has conquered the world. He hungered—yet he fed thousands. He is indeed “living, heavenly bread.” He thirsted—yet he exclaimed: “Whosoever thirsts, let him come to me and drink. Indeed he promised that believers would become fountains. He was tired—yet he is the rest of the weary and the burdened. He was overcome by heavy sleep—yet he goes lightly over the sea, rebukes winds, and relieves the drowning Peter. He pays tax—yet he uses a fish to do it; indeed he is emperor over those who demand the tax. He is called a “Samaritan, demonically possessed”—but he rescues the man who came down from Jerusalem and fell among thieves.
Yes, he is recognized by demons, drives out demons, drowns deep a legion of spirits, and sees the prince of demons falling like lightning. He is stoned, yet not hit; he prays, yet he hears prayer. He weeps, yet he puts an end to weeping. He asks where Lazarus is laid—he was man; yet he raises Lazarus—he was God.
He is sold, and cheap was the price—thirty pieces of silver; yet he buys back the world at the mighty cost of his own blood. A sheep, he is led to the slaughter—yet he cures every disease and every weakness. He is brought up to the tree and nailed to it—yet by the tree of life he restores us. Yes, he saves even a thief crucified with him; he wraps all the visible world in darkness. He is given vinegar to drink, gall to eat—and who is he? Why, one who turned water into wine, who took away the taste of bitterness, who is all sweetness and desire. He surrenders his life, yet he has power to take it again. Yes, the veil is rent, for things of heaven are being revealed, rocks split, and dead men have an earlier awakening. He dies, but he vivifies and by death destroys death. He is buried, yet he rises again. He goes down to Hades, yet he leads souls up, ascends to heaven, and will come to judge quick and dead. (Or. 29.20)
Jesus Christ is one divine subject of whom is predicated two sets of attributes and activities, human and divine. Gregory presents him in dynamic terms as the “agent of the drama of salvation who unites with himself the fullness of human existence” (p. 185). He does not analyze the identity of the incarnate Son through philosophical conceptuality, as in post-Chalcedonian Byzantine thought or medieval scholasticism. He interprets Christ by reference to the economy of salvation—hence Beeley’s preference for speaking of the Incarnation in terms of the Word’s assumption of “human existence” rather than “human nature.” The latter sounds too abstract and analytical for the dynamic narrative-based christology of the Nazianzen. This does not mean that Gregory does not occasionally employ two-natures language (see below), but he does so sparingly. As with with his trinitarian terminology, his use of language is supple, flexible, multivalent. What is important for Gregory is faithful proclamation of the enfleshed God as recounted in Holy Scripture, not philosophical precision regarding the mechanics of incarnation.
To make clear the divine identity of Jesus, Gregory is willing to speak of the pre-existent Son: “He whom presently you scorn was once transcendent, over even you. He who is presently human was incomposite. He remained what he was; what he was not, he assumed” (Or. 29.19). In the Incarnation the Word becomes “Man and God blended. They became a single whole [one entity], the stronger side predominating, in order that I might be made God to the same extent that he was made man” (Or. 29.19). But Gregory is not interested in speculation about the logos asarkos. As the last clause suggests, his principal concern is the crucified and risen Lord who now deifies the faithful.
Gregory forged his christological reflection in a three-front battle against Eunomius, Diodore of Tarsus, and Apollinarius of Laodicea. Against each he presses the same unitive christology. When Gregory was sent by the synod of Antioch (379) to assume leadership of the struggling Nicene congregation in Constantinople, he was expressly commissioned to preach against the growing Apollinarian heresy; but after his arrival he decided to focus his attentions both on Eunomian subordinatinism but also on the christological dualism characteristic of Antiochene theology. Diodore is his unnamed target. Beeley summarizes the views of Diodore of Tarsus:
The central principle of Diodore’s Christology is that the divine Word of God and the human Jesus are two distinct subjects or beings, and they must not be mingled or confused with one another. Jesus is clearly distinct from the Word; he is neither the Word present in human form, nor human existence literally or essentially united with the Word, as Apollinarius alleged. The human being Jesus of Nazareth is from the seed of Abraham and David (see Rom 1:3) and is human in his nature and being (ousia) (SD 3, 6, 11); whereas the Divine Son is naturally begotten of God the Father and shares his being (SD 10-13). Jesus and the Son of God are therefore different in nature from one another, and each one is a perfect and complete entity: full God and a full human being (SD 5, 8). In reply to Apollinarius, then, Diodore strongly insists the the Word did not “unite” or “mingle” with human flesh, but rather “indwelt” the man Jesus as in a temple (BD 20; SD 4). Christ is the Son of God by grace, not by essence, nature, or union. (p. 181)
Antiochene christology is often presented as driven by a concern to emphasize and protect the humanity of the Savior, but even more decisive, perhaps, was the concern to maintain the impassibility of the Creator, which Apollinarius’s language of union and mixture seemed to threaten (p. 182). Gregory shared with the Antiochenes the doctrine of divine impassibility, yet his grasp of the soteriological import of the Incarnation compelled him to keep together that which must not be divided if sinners are to share in the gift of theosis.
Against the dualism of Diodore, St Gregory the Theologian asserts the one incarnate God:
We affirm and teach one and the same God and Son, at first not man but alone and pre-eternal, unmixed with body and all that belongs to the body, but finally human being too, assumed for our salvation, the same passible in flesh, impassible in Godhead, bounded in body, boundless in spirit, earthly and heavenly, visible and known spiritually, finite and infinite: so that by the same, whole man and God, the whole human being fallen under sin might be fashioned anew. … Two natures there are, God and man (since there are both soul and body), but not two “sons” or two “Gods.” … In sum: the constituents of our Savior are different things (since invisible and visible, timeless and temporal, are not the same), but not different people—God forbid! The pair is one by coalescence, God being “inhominized” and man “deified”—or however we want to put it. (Ep. 101.4-5)
Note the word “coalescence,” which renders the Greek word synkrasis. Two of Gregory’s favorite ways of speaking of the theandric union are “mixture” (mixis) and “blending” (krasis). These metaphors carry their own dangers, but they well intimate the profound coinherence of divinity and humanity in Jesus Christ.