St. Gregory the Theologian, Oration 38, Section 2:
Again the darkness is dissolved, again the light is established, again Egypt is punished by darkness. Again Israel is illumined by a pillar. Let the people sitting in the darkness of ignorance see a great light of knowledge. “The old things have passed; behold, all things have become knew.” The letter withdraws, the spirit advances; the shadows have been surpassed, the truth has entered after them. Melchizedek is completed, the motherless one becomes fatherless; he was motherless first, fatherless second. The laws of nature are dissolved. The world above must be filled. Christ commands, let us not resist. “All nations clap your hands,” “for to us a child is born, and to us a son is given, the power is on his shoulder,” for he is lifted up along with the cross, and he is called by the name “angel of great counsel,” that of the Father. Let John proclaim, “Prepare the way of the Lord.” I myself will proclaim the power of this day. The fleshless one take flesh, the Word is made coarse, the invisible one is seen, the impalpable one is touched, the timeless one makes a beginning, the Son of God becomes the Son of Man, “Jesus Christ, the same yesterday and today and for the ages.” Let Jews be scandalized, let Greeks mock, let heretics talk till their tongues ache. They will believe when they see him ascend into heaven, and if not then, at least when they see him coming from heaven and sitting as judge.