C.S. Lewis describes the Incarnation as follows:
“One may think of a diver first reducing himself to nakedness, then glancing in mid-air, then gone with a splash, vanished, rushing down through green and warm water into black and cold water, down through the increasing pressure into the deathlike region of ooze and slime and old decay, and then back up again, back to color and light, his lungs almost bursting until suddenly he breaks the surface again, holding in his hand the dripping, precious thing he went down to recover. That dripping, precious thing is you and I, and Advent is when we celebrate his coming down to us.”
Bruce Thielemann uses the telescope on Mt. Palomar as an analogy for Christ’s coming in the flesh. That huge telescope (it takes an hour just to focus it on a particular point) draws the light of stars from across the galaxy and compresses it onto a single square-inch photographic plate. “But that is nothing compared to the way God focused himself in that baby.”
The Apostle Paul describes the reality of Christmas best of all:
“Although He existed in the form of God, (He) did not regard equality with God a thing to be grasped, but emptied Himself, taking the form of a bond-servant, being made in the likeness of men. Being found in appearance as a man, He humbled himself by becoming obedient to the point of death, even death on a cross.”
It is beyond human comprehension how the Son of God, the Second Person of the Trinity, “emptied Himself” into human flesh and “dwelt among us,” but He did. This is the witness of Scripture, the confession of the Church, and the only hope for humankind.