How did Christmas day feel to God? Imagine for a moment becoming a baby again. God as a fetus! Or imagine yourself becoming a sea slug — that is probably closer. On that day in Bethlehem, the Maker of All That Is took form as a helpless, dependent newborn.
Philip Yancey, Disappointment with God
Therefore the Lord himself will give you a sign: The virgin will conceive and give birth to a son, and will call him Immanuel.
Isaiah 7:14 NIV