Ask the average Christian why it was necessary for God to bring about the incarnation of Christ, the central mystery of Christian doctrine, and he might feel that he knows the answer. He might say simply that it was necessary for man’s salvation. But the answer offered by Athanasius the Great in On the Incarnation, from St Vladimir’s Seminary (SVS) Press, turns out to be much deeper, more complicated and, ultimately, more satisfying.

Saint Athanasius lived in fourth century Egypt and was the bishop of Alexandria. He was noted as the chief defender of Trinitarianism against Arianism. “His very name was synonymous with Orthodoxy,” writes translator John Behr, who adds that the influence of On the Incarnation “on all later theology cannot be overstated.”

In a wide-ranging way, Athanasius explains the incarnation, but he does so by writing about the totality of God’s work, from creation to regeneration. He does this, he writes, so that “you may have an even greater and fuller piety towards him, for the more he is mocked by unbelievers by so much he provides a greater witness of his divinity, because what humans beings cannot understand as impossible, these he shows to be possible (cf. Matt 19.26), and what human beings mock as unseemly, these he renders fitting by his own goodness . . .”

He writes that it is necessary to speak about the creation of the universe because it was only fitting that the one who created all things would be the same one who works the salvation of man. He also explains that God granted man the gift of being created in his likeness as a rational being and relates it to the incarnation so that “you might know that our own cause was the occasion of his descent and that our own transgression evoked the Word’s love for human beings, so that the Lord both came to us and appeared among human beings.”

Furthermore, it was unworthy of the goodness of God that his work should disappear because of the sins of men and the work of demons. Repentance was not enough because it does not change “what is natural, but merely halts sin.”

For the Word, realizing that in no other way would the corruption of human beings be undone except, simply, by dying, yet being immortal and the Son of the Father the Word was not able to die, for this reason he takes to himself a body capable of death, in order that it, participating in the Word who is above all, might be sufficient for death on behalf of all, and through the indwelling Word would remain incorruptible, and so corruption might henceforth cease from all by the grace of the resurrection.

On the Incarnation is rich with metaphors. God is the king who stays in a city and confers great honor to it, so Christ does so by inhabiting a human body. Christ is the landowner who, if need be, comes himself to ensure that the lands begun under him do not pass to others but to his friends. And he is the good teacher who “condescends to teach by simpler means those who are not able to benefit from more advanced things.” He writes:

For since human beings, having rejected the contemplation of God and as though sunk in an abyss with their eyes held downwards, seeking God in creation [genesis] and things perceptible, setting up for themselves mortal humans and demons as gods, for this reason the lover of human beings and the common Savior of all, takes to himself a body and dwells as human among humans and draws to himself the perceptible senses of all human beings, so that those who think that God is things corporeal might, from what the Lord wrought through the actions of the body, know the truth and through him might consider the Father.

This edition includes an introduction by C.S. Lewis who writes: ““When I first opened his De Incarnatione I soon discovered by a very simple test that I was reading a masterpiece . . . only a master mind could, in the fourth century, have written so deeply on such a subject with such classical simplicity.”