St. Leo the Great
As yonder visible light affords pleasure to eyes that are unimpaired, so to sound hearts does the Saviour’s nativity give eternal joy.
And we must not keep silent about it, though we cannot treat of it as we ought.
For we believe that what Isaiah says, “who shall declare his generation?” (Isaiah 53:8) applies not only to that mystery, whereby the Son of God is co-eternal with the Father, but also to this birth whereby “the Word became flesh.”
God, the Son of God, equal and of the same nature from the Father and with the Father, Creator and Lord of the Universe, is completely present everywhere, and completely exceeds all things.
In the due course of time, which runs by His own disposal, He chose for Himself this day on which to be born of the blessed virgin Mary for the salvation of the world, without loss of the mother’s honour.
Her virginity was violated neither at the conception nor at the birth: “that it might be fulfilled,” as the Evangelist says, “which was spoken by the Lord through Isaiah the prophet, saying, behold the virgin shall conceive in the womb, and shall bear a son, and they shall call his name Emmanuel, which is interpreted, God with us” (Matt. 1:22, 23).
This wondrous child-bearing of the holy Virgin produced in her offspring one person which was truly human and truly Divine.
[...] Thus in the whole and perfect nature of true man was true God born, complete in what was His own, complete in what was ours. And by “ours” we mean what the Creator formed in us from the beginning, and what He undertook to repair.
For what the deceiver brought in, and man deceived committed, had no trace in the Saviour; nor because He partook of man’s weaknesses, did He therefore share our faults.
He took the form of a slave without stain of sin, increasing the human and not diminishing the divine. For that “emptying of Himself,” whereby the Invisible made Himself visible, was the bending down of pity, not the failing of power.
In order therefore that we might be called to eternal bliss from our original bond and from earthly errors, He came down Himself to us to Whom we could not ascend.
Although there was in many the love of truth, yet the variety of our shifting opinions was deceived by the craft of misleading demons.
[...] To remove this mockery, whereby men’s minds were taken captive to serve the arrogant devil, the teaching of the Law was not sufficient, nor could our nature be restored merely by the Prophets’ exhortations.
But the reality of redemption had to be added to moral injunctions, and our fundamentally corrupt origin had to be re-born afresh.
Leo the Great (c.400-461): Sermon 23, 1-3.
