“For [Cyril of Alexandria], life consists of participation in God’s life. Holiness and righteousness are participation in God’s holiness. Freedom from sin is participation in God, the one who has never been a slave to sin. If one were to conceive of these characteristics as separable qualities, one could imagine that a person who receives these could then pass them on to another or help another obtain them. ... [T]his is essentially the way Theodore and Nestorius understand grace. But for Cyril, these gifts are inseparable from the person of the giver, God himself. The way God gives us life and holiness is by giving us Christ, therefore causing us to share in the qualities that Christ possesses. Since Christ’s giving of himself to us constitutes God’s giving us participation in himself, Christ must be God by nature, not merely by a grace borrowed from another.”
—Donald Fairbairn, Grace and Christology in the Early Church (New York: Oxford UP, 2003), 72.