Here are some poetic words from Saint Augustine’s Sermon 69: On the same words, John 1: “In the beginning was the Word, etc.” excerpted from the Nicene and Post-Nicene Fathers edited by Philip Schaff. There are some beautiful lines here on the Incarnation—the Word of God becoming flesh—that could make this a Christmas sermon.
Do not follow the current of the flesh. For this flesh is indeed a current; for it has none abiding. As it were from a kind of secret fount of nature men are born, they live, they die; or whence they come, or whither they go, we know not. It is a hidden water, till it issue from its source; it flows on, and is seen in its course; and again it is hidden in the sea. Let us despise this stream–flowing on, running, disappearing—let us despise it. “All flesh is grass, and all the glory of flesh is as the flower of grass. The grass withers, the flower falls away.” Would you endure? “But the word of the Lord endures forever.” [1 Peter 1:24-25]
But in order to succour us, “The Word was made Flesh, and dwelt among us.” What is, “The Word was made Flesh?” The gold became grass. It became grass for to be burned; the grass was burned, but the gold remained; in the grass It perishes not, yea, It changed the grass. How did It change it? It raised it up, quickened it, lifted it up to heaven, and placed it at the right Hand of the Father. But that it might be said, And the Word was made Flesh, and dwelt among us, let us recollect awhile what went before. He came unto His Own, and His Own received Him not. But as many as received Him, to them gave He power to become the sons of God. To become, for they were not; but He was Himself in the beginning. He gave them then power to become the sons of God, to them that believe in His Name; who were born not of blood, nor of the will of the flesh, nor of the will of man, but of God. Lo, born they are, in whatever age of the flesh they may be; ye see infants; see and rejoice. Lo, they are born; but they are born of God. Their mother’s womb is the water of baptism. …
But how, one will say, can it be, that the Word of God, by whom the world is governed, by whom all things both were, and are created, should contract Himself into the womb of a Virgin; should abandon the world, and leave the Angels, and be shut up in one woman’s womb? Thou skillest not to conceive of things divine. The Word of God (I am speaking to you, O man, I am speaking to you of the omnipotence of the Word of God) could surely do all, seeing that the Word of God is omnipotent, at once remain with the Father, and come to us; at once in the flesh come forth to us, and lay concealed in Him. For He would not the less have been, if He had not been born of flesh. He was before His own flesh; He created His own mother. He chose her in whom He should be conceived, He created her of whom He should be created. Why do you marvel? It is God of whom I am speaking to you: The Word was God.