Cyril of Alexandria (ca. A.D. 378-444) was a hard-nosed church politician who restlessly campaigned against the heresies of his day. As Bishop of Alexandria (412-444) he battled against the teaching of Bishop Nestorius of Constantinople, who was deposed in 431 for teaching in such a way as to leave the impression that Christ was really two persons united only by will and not by nature. This incomplete assumption of the human nature by the eternal God left human nature with a salvation by will, not by divine act. Nestorius taught, like modern moralists, that the Christian was to emulate his life and piety of Christ and thus to find salvation. Salvation became a choice of the human will rather than the monergistic act of God. The incarnation was not complete, almost as though there were two Christ's; one, Jesus the man, and the other, the divine Logos.

This debate between Cyril and Nestorius is the eastern analog to the debate between Augustine and the Pelagians. In the east, the debate was always couched in terms of Christology; in the west, in terms of soteriology. In the bigger scheme of things both Augustine and Cyril contributed enormous theological gifts to the church, each defending divine monergism in his own way. One might say that Cyril's eastern pattern has experienced a revival partly through the influence of Luther for whom righteousness before God and the person of Christ were inseparable, even if distinguishable. There is something profoundly salutary, though, in the eastern insistence on seeing everything through the lens of Christology that is being appropriated again in many theological circles today. Christ is the one who brings salvation and salvation is about Christ.

Cyril echoed his predecessor, Athanasius, for whom the principal was "what was not assumed could not be saved." An incomplete assumption of the human nature, implied a less than complete salvation. Here the Pelagian error leaps out at us. If Christ's work to save us was incomplete, then we have to pick up where He left off and finish the effort. It is no more likely that we could finish salvation once started than it would be to start what is not yet begun. Cyril saw that a full and complete union between the two natures in Christ is essential to our salvation. No half measures would do.

"We believe therefore, not in one like us honored with divinity by grace, lest we be found worshippers of a man. Rather we believe in the Lord who appeared in servant's form, and who was truly like us and in human nature, yet remained God. For God the Word, when He took flesh, did not lay down what He was, but is conceived as the same God alike and Man. This is the right faith. But if anyone says, 'What harm if a man like us be thought of as laying hold on divinity rather than God being made man?' We shall answer that there are a thousand things which may be brought to bear against this, and which all tell us that we ought firmly to strive against it and not believe it.

"Before anything else, let us look at the circumstance of the flesh and thoroughly investigate the nature of our condition. The nature of man, imperiled, brought down to the worst ill, condemned to being cursed and to death and involved in the toils of sin, straying and in darkness, did not know Him who is by nature truly God. Instead, it worshipped the creature more than the Creator. How then could it be freed from such ills? Or do we say that it was right for human nature to lay hold of the divine Nature, even while it did not at all know what the dignity of the supreme Nature is, given that it was possessed by ignorance and darkness, and denied by the filth of sin? How could it mount up to the purest Nature and lay hold on glory which none can lay hold of, except he receive it as a gift? Suppose that by knowledge (and through knowing we say that it lays hold of it), who is to teach it? For how shall they believe except they hear (Rm 10:14)? But this is not to take hold of divinity, nor to seize the glory that belongs to it.