The Christmas story isn’t about a baby in a manger. It isn’t about a virgin mother. It isn’t even about prophecies about a messiah.

The Christmas story is about how God became a man. It’s about why Jesus became like us. It’s about how you and I could become like God. The Christmas story is about why we must become like Jesus.

Many of us know how the second person of the Trinity became a man. We know that 2000 years ago in Israel a young woman named Mary was betrothed to a man named Joseph. We know that the angel Gabriel announced to her that though she is a virgin, she will conceive a child by the Holy Spirit named Jesus, the promised Messiah. We know that though Jesus is the Son of God, and not Joseph’s biological son, Joseph married Mary and led his pregnant wife to Bethlehem, where Jesus was born.

We also know why Jesus left heaven for earth. We know that the Son of Man came to find the lost. We know that he came to give his life as a ransom for many. We know that he came into the world to save sinners. We know that Jesus came to die so that we might live. We know that he suffered death on a cross so that he would reconcile us to God.

That however doesn’t answer why God became a man. It doesn’t answer why Jesus had to become like us in every way. It doesn’t explain why it was necessary for the Son of God to become a fetus. Have you ever wondered why Jesus didn’t just appear in the form of a man as he did with Abraham, Moses, and Jacob in the Old Testament period? Why did Jesus have to become a man?

God became a man because man sinned against God. When Adam and Eve disobeyed God in the Garden of Eden, humanity became corrupted and condemned. That is why Adam and Eve’s son, Cain, murdered his brother, Abel. That is why children learn to lie on their own. That is why you and I have not gone a single day without sinning. We are unrighteous by nature, and a righteous God cannot overlook that. Which prompts Job to ask, “how then can man be in the right before God? How can he who is born of woman be pure? (Job 25:4)”

Through Adam, humanity cannot be right before God; through Adam, no one born of a woman can be pure–except for Jesus. He is conceived by the Holy Spirit through a virgin birth. He is born righteous. He is born pure. Though he is fully man just like us, he is not corrupted by Adam’s sin. For that reason, though Adam’s sin made many sinners, Jesus became a man so that he could make many righteous.

That is the Christmas story. The Son of God became the son of a woman. The faithful creator became a fetus. The bearer of God’s wrath became a boy. The maker of the universe became a man. He was tempted like us but without sin, unlike us. He obeyed God in the garden of Gethsemane, unlike Adam in the Garden of Eden.

The Christmas story isn’t just about a baby in a manger. It’s also about a man on a cross. It isn’t just about a virgin woman bearing the Son of God. It’s also about the Son of God bearing our sins. It isn’t just about the importance of Jesus’ birth, it’s also about the importance of his death and resurrection for our justification. That is why God became a man.

Jesus became a man to take our place in judgement and receive God’s wrath for sin. He became a man so that being fully God and being fully man, he could fully restore reconcile humanity to God. He became a man so that he could give all who trust in him his righteousness, the righteousness of God. He became a man so that he could die for sinners. He became a man so that he could rise again for our justification. He became a man so that we could be sanctified and glorified in Him. He became a man, receiving a mother on earth, so that we could receive a father in heaven. Jesus became like us on earth so that we would become like in Heaven. God became a man so that we could become like him.