C.S. Lewis says that “In the Christian story God descends to reascend.”
He comes down; down from the heights of absolute being into time and space, down into humanity.... But he goes down to come up again and bring the whole ruined world up with Him. One has the picture of a strong man stooping lower and lower to get himself underneath some great complicated burden. He must stoop in order to lift, he must almost disappear under the load before he incredibly straightens his back and marches off with the whole mass swaying on his shoulders.
Or one may think of a diver, first reducing himself to nakedness, then glancing in midair, then gone with a splash, vanished, rushing down through green and warm water into black and cold water, down through increasing pressure into the deathlike region of ooze and slime and old decay; then up again, back to color and light, his lungs almost bursting, till suddenly he breaks surface again, holding in his hand the dripping, precious thing that he went down to recover. He and it are both colored now that they have come up into the light: down below, where it lay colorless in the dark, he lost his color too.
George Herbert offers this truth in poetic form:
Hast thou not heard, that my Lord Jesus di’d?
Then let me tell thee a strange storie.
The God of power, as He did ride
In His majestic robes of glorie,
Reserv’d to light; and so one day
He did descend, undressing all the way.
The starres His tyre of light and rings obtain’d,
The cloud His bow, the fire His spear,
The sky His azure mantle gain’d.
And when they ask’d, what He would wear;
He smil’d and said as He did go,
He had new clothes a making here below.
In Christmas we bow before an eternal miracle: The God of glory did descend
into our human darkness,
that we might be made the children of Light.