You may be wondering why we are discussing the origin of men when we set out to talk about the Word's becoming Man. The former subject is relevant to the latter for this reason: it was our sorry case that caused the Word to come down, our transgression that called out His love for us, so that He made haste to help us and to appear among us.
It is we who were the cause of His taking human form, and for our salvation that in His great love He was both born and manifested in a human body. For God had made man thus (that is, as an embodied spirit), and had willed that he should remain in incorruption. But men, having turned from the contemplation of God to evil of their own devising, had come inevitably under the law of death. Instead of remaining in the state in which God had created them, they were in process of becoming corrupted entirely, and death had them completely under its dominion.
For the transgression of the commandment was making them turn back again according to their nature; and as they had at the beginning come into being out of non-existence, so were they now on the way to returning, through corruption, to non-existence again.
The presence and love of the Word had called them into being; inevitably, therefore when they lost the knowledge of God, they lost existence with it; for it is God alone Who exists--evil is non-being, the negation and antithesis of good.
...The Word perceived that corruption could not be got rid of otherwise than through death; yet He Himself, as the Word, being immortal and the Father's Son, was such as could not die. For this reason, therefore, He assumed a body capable of death, in order that it, through belonging to the Word Who is above all, might become in dying a sufficient exchange for all, and, itself remaining incorruptible through His indwelling, might thereafter put an end to corruption for all others as well, by the grace of the resurrection.