Great indeed was the faith of Abraham. . . It was necessary to go beyond human reasoning. . . to manifest also something more.
St. John Chrysostom
Homily XXV on Hebrews XI, 1,2. translation found in The Bible and the Holy Fathers for Orthodox, Monastery Books, St. Vladimir's Seminary Press, Crestwood, NY 2003, p. 955., 4th Century
The tribes of Judah and Levi were united by a fusion of their lines of descent, and that is why Matthew assigns Christ's family to the tribe of Judah. And the Apostle says, 'for our Lord has sprung out of Judah' (Heb. 7:14).
St. Ambrose of Milan
Seven Exegetical Works, 4th Century
Lift up your voice, O Zion, holy city of God,
Proclaim the divine memory of the Fathers.
With Abraham, Isaac, and Jacob
Honor one whose memory is eternal:
For behold, with Judah and levi we magnify Moses the Great,
And with him the wonder-working Aaron.
With David we celebrate the memory of Joshua and Samuel,
Calling all with divine songs and praise
To the prefeast of Christ's Nativity,
Praying that we may receive His goodness,
For it is He who grants the world great mercy.
Orthros of the Sunday before the Nativity
Translation from "The Winter Pascha" SVS Press
I too will proclaim the greatness of this day: the Immaterial become incarnate, the Word is made flesh, the invisible makes itself seen, the intangible can be touched, the timeless has a beginning, the Son of God becomes the Son of Man, Jesus Christ, always the same, yesterday, today and forever. . . This is the solemnity we are celebrating today: the arrival of God among us, so that we might go to God, or more precisely, return to Him. . . Revere the nativity which releases you from the chains of evil. Honor this tiny Bethlehem which restores Paradise to you. Venerate this crib; because of it you who were deprived of meaning (logos) are fed by the divine Meaning, the divine Logos Himself.
St. Gregory the Theologian
Oration 38, For Christmas (Patrologia Graeca, 36, 664-5) found in The Roots of Christian Mysticism by Olivier Clement, New City Press, NY, p. 41, 330-390
That God should have clothed Himself with our nature is a fact that should not seem strange or extravagant to minds that do not form too paltry an idea of reality. Who, looking at the universe, would be so feeble-minded as not to believe that God is all in all; that He clothes Himself with the universe, and at the same time contains it and dwells in it? What exists depends on Him Who exists, and nothing can exist except in the bosom of Him Who is.
If then all is in Him and He is in all, . . .Indeed, if the presence of God in us does not take the same form now as it did then, we can at least agree in recognizing that He is in us today no less tha He was then. Today, He is involved with us in as much as He maintains creation in existence. Then He mingled Himself with our being to deify it by contact with Him, after He had snatched it from death. . . For His resurrection becomes for mortals the promise of their return to immortal life.
St. Gregory of Nyssa, Catechetical Orations, 25 (Patrologia Graeca, Migne.)
Found in The Roots of Christian Mysticism by Olivier Clement, New City Press, NY, pp. 37-38, 330-395
This is the reason why the Word of God was made flesh, and the Son of God became Son of Man: so that we might enter into communion with the Word of God, and by receiving adoption might become Sons of God. Indeed we should not be able to share in immortality without a close union with the Immortal. How could we have united ourselves with immortality if Immortality had not become what we are, in such a way that we should not be absorbed by it, and thus we should be adopted as Sons of God?
Irenaeus of Lyons, Against Heresies, III. 19,1
Sources Chretiennes, Cerf, Paris, as found in The Roots of Christian Mysticism by Olivier Clement, p. 38, 130-208