Quotes about the Incarnation from throughout Christian History.
Those who assert that he was a mere man, begotten by Joseph ... being ignorant of him who from the virgin is Emmanuel ... are deprived of his gift, which is eternal life. Not receiving the incorruptible Word, they remain in mortal flesh and are debtors to death, not obtaining the antidote of life. To these the Word says, mentioning his own gift of grace, "I said, 'You are all the sons of the Highest and gods, but you shall die like men.'"
Undoubtedly, he speaks these words to those who have not received the gift of adoption, but who despise the incarnation of the pure generation of the Word of God, defraud human nature of promotion into God, and prove themselves ungrateful to the Word of God, who became flesh for them. For it was for this purpose that the Word of God was made man, and he who was the Son of God became the Son of Man, so that man, having been taken into the Word and receiving the adoption, might become the son of God. For there is no other way we could have attained to incorruptibility and immortality unless we had been united to incorruptibility and immortality. How could we be joined to incorruptibility and immortality unless, first, incorruptibility and immortality had become that which we are, so that the corruptible might be swallowed up by incorruptibility, and the mortal by immortality, so that we might receive the adoption of sons? (Against Heresies III:19:1)