On the Incarnation...
It was necessary for nature to be strengthened and renewed, and for the path of virtue to be indicated and effectively taught (didachthenai aretes hodon), the path that leads away from corruption and toward eternal life…So there appeared on the horizon of history the great sea of love that God bears toward man (philanthropias pelagos).
St. John Damascene
For this purpose, then, the incorporeal and incorruptible and immaterial Word of God comes to our realm, howbeit he was not far from us (Acts 17:27) before. For no part of Creation is left void of Him: He has filled all things everywhere, remaining present with His own Father. But He comes in condescension to show loving-kindness upon us, and to visit us. And seeing the race of rational creatures in the way to perish, and death reigning over them by corruption; seeing, too, that the threat against transgression gave a firm hold to the corruption which was upon us, and that it was monstrous that before the law was fulfilled it should fall through: seeing, once more, the unseemliness of what had come to pass: that the things whereof He Himself was Artificer were passing away: seeing, further, the exceeding wickedness of men, and how little by little they had increased it to an intolerable pitch against themselves: and seeing, lastly, how all men were under penalty of death: He took pity on our race, and had mercy on our infirmity, and condescended to our corruption, and, unable to bear that death should have the mastery — lest the creature should perish, and His Father's handiwork in men be spent for nought — He takes unto Himself a body, and that of no different sort from ours. For He did not simply will to become embodied, or will merely to appear. For if He willed merely to appear, He was able to effect His divine appearance by some other and higher means as well. But He takes a body of our kind, and not merely so, but from a spotless and stainless virgin, knowing not a man, a body clean and in very truth pure from intercourse of men.
St. Athanasius the Great
Make ready, O Bethlehem; for Eden hath been opened for all.
Prepare, O Ephratha; for the Tree of life hath blossomed forth
in the cave from the Virgin;
for her womb did appear as a supersensual paradise
in which is planted the divine Plant,
whereof eating we shall live and not die as Adam.
Verily, Christ shall be born, raising the likeness that fell of old.
Troparion for the Forefeast of the Nativity of Christ