by St. Gregory the Theologian, excerpted from a homily (Festal Oration 38) given by St. Gregory while Archbishop of Constantinople, on the Feast of the Nativity in the year 380.
Christ is born, give glory; Christ is from the heavens, go to meet Him; Christ is on earth, be lifted up. "Sing to the Lord, all the earth," and, to say both together, "Let the heavens be glad and let the earth rejoice," for the Heavenly One is now earthly. Christ is in the flesh, exult with trembling and joy; trembling because of sin, joy because of hope. Christ comes from a Virgin; women, practice virginity, that you may become mothers of Christ. Who would not worship the One "from the beginning"? Who would not glorify "the Last"?
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 siting in the darkness of ignorance see a great light of knowledge. "The old things have passed; behold, all things have become new." 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 takes flesh, the Word is made coarse, the invisible One seen, the impalpable One is touched, the timeless One makes a beginning, the Son of God becomes a 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.