And the Word was made flesh, and dwelt among us.
The Incarnation of Our Lord and Saviour Jesus Christ - the teaching that the eternal God, existing "before" time, Maker of all things: visible and invisible, He Who is without beginning or end, the ineffable, unknowable God, could become flesh and be born as a tiny baby, is completely absurd. And it is precisely this absurdity that makes it all the more awe-inspiring when we realise that it is indeed true. It is truly a paradox, and there is so much of our hymnody and poetry that reflects this. Only today, I came across this from Blessed Augustine of Hippo:
Who is this infant? Infant, He is called, that is, "in-fans", one who cannot speak. So that He is both speechless infant and Word of God.
The Troparion for the Feast of the Nativity in the Byzantine Rite encompasses something of this in the wise men coming from afar to pay homage to this baby:
Thy Nativity, O Christ our God, hath shined upon the world the light of knowledge. For thereby, they that worshipped the stars were taught by a star to worship Thee, the Sun of Righteousness, and to know Thee, the Dayspring from on high. O Lord, glory be to Thee!
I think, though, that what illustrates this best for me is the Christmass carol, The Great God of Heaven is come down to Earth. The entire carol is simply a series of contrasts between the human and divine natures of Christ, and a rejoicing in the perfect hypostatic union of the two. Here are some excerpts:
The Great God of heaven is come down to earth,
his mother a virgin, and sinless his birth;
the Father eternal, his Father alone;
He sleeps in the manger, He reigns on the throne.
Then there's this wonderfully homely couplet in the second verse:
Before him their faces the Seraphim hide,
while Joseph stands waiting, unscared, by his side.
But finally, what always brings awe to my heart and a tear to my eye, is this verse:
O wonder of wonders! which none can unfold:
the Ancient of Days is an hour or two old,
the Maker of all things is made of the earth,
Man is worshipped by Angels, and God comes to birth!
I don't really think that there's anything more to be said, except perhaps Marana'tha: come, Lord Jesus!