In the same region there were some shepherds staying out in the fields and keeping watch over their flock by night. And an angel of the Lord suddenly stood before them, and the glory of the Lord shone around them; and they were terribly frightened. But the angel said to them, "Do not be afraid; for behold, I bring you good news of great joy which will be for all the people; for today in the city of David there has been born for you a Savior, who is Christ the Lord." (Luke 2:8-11)
The incarnation of Jesus Christ is the manifestation of God in human flesh. Jesus Christ is both the Son of God and the Son of man, both fully deity and fully humanity. Paraphrasing a quote from Charles H. Spurgeon; "This is either the most ridiculous and foolish lie or the most amazing revelation. No one can comfortably remain undecided about the incarnation."
And yet most people, even many of those who call themselves Christians, don't understand the significance of the incarnation. When Jesus was born into the human race, God willingly humbled Himself; Being found in appearance as a man, He humbled Himself by becoming obedient to the point of death, even death on a cross.(Philippians 2:8) He was born to die in order to save us from the penalty of sin. For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord. (Romans 3:23)
Do you truly understand and believe in the significance of the incarnation and the birth of Jesus Christ? Immanuel-- God with us! Maranatha!