The Importance of the Incarnation of Jesus Christ...by Athanasius

John 1:1 In the beginning was the Word, and the Word was with God, and the Word was God. John 1:14 ¶ And the Word became flesh, and dwelt among us, and we saw His glory, glory as of the only begotten from the Father, full of grace and truth. John 1:18 No one has seen God at any time; the only begotten God who is in the bosom of the Father, He has explained Him.

Athanasius (c. 300-373), On the Incarnation
(New York: St. Vladimir’s Seminary Press, 1993), sect. 8, p. 34.
"Thus, taking a body like our own, because all our bodies were liable to the corruption of death, He surrendered His body to death in place of all, and offered it to the Father. This He did out of sheer love for us, so that in His death all might die, and the law of death thereby be abolished because, having fulfilled in His body that for which it was appointed, it was thereafter voided of its power for men. This He did that He might turn again to incorruption men who had turned back to corruption, and make them alive through death by the appropriation of His body and by the grace of His resurrection. Thus He would make death to disappear from them as utterly as straw from fire."

Ibid., sect. 9, p. 35.
"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. It was by surrendering to death the body which He had taken, as an offering and sacrifice free from every stain, that He forthwith abolished death for His human brethren by the offering of the equivalent. For naturally, since the Word of God was above all, when He offered His own temple and bodily instrument as a substitute for the life of all, He fulfilled in death all that was required."