I've heard a story about a man who wanted to save some geese from the cold as an illustration of the incarnation. The only way he could save them was to release one of his own geese to guide them to the warmth of the barn.
I've heard the incarnation related to us becoming a worm in order to save worms.
But those aren't quite right.
As astounding as the incarnation is--that God became a man, that the One who created billions of galaxies with a word came to live with us, as one of us--as amazing as that is, what's more amazing is why.
He came because He loves us. That man cared about the well-being of those geese, but it was a simple thing to save them. He cared, but he didn't love them. We wouldn't become a worm because we don't love the worms.
God wasn't just doing a good deed. His love compelled Him. He can't live without us. He loves us. Really, deeply loves us.
That's the most amazing thing of all.