From Tim Keller
We sing it every year in our Christmas carols, especially in “Hark! The Herald Angels Sing” when we cry out: “Veiled in flesh, the Godhead see; hail the incarnate Deity.”
The Apostles’ Creed doesn’t use it, but it teaches the doctrine of it when we read, “conceived by the Holy Ghost, born of the Virgin Mary.”
Incarnation. If you understand the word incarnation, you’ll understand what Christmas is about.
Christmas is frankly doctrinal. The invisible has become visible, the incorporeal has become corporeal. In other words, God has become human.
This is not only a specific doctrine, but it’s also unique. Doctrine always distinguishes you. One of the reasons we’re afraid to talk about doctrine is because it distinguishes us from others.
Here’s why the doctrine of Christmas is unique. On one hand, you’ve got religions that say God is so immanent in all things that incarnation is normal. If you’re a Buddhist or Hindu, God is immanent in everything. On the other hand, religions like Islam and Judaism say God is so transcendent over all things that incarnation is impossible.