Summary: The sacred mystery of Christmas is the Incarnation, that God became flesh and made His dwelling among us. The world opposes this mystery as irrational and offensive, because it points to our fallen nature and need for a Savior.

The Mystery of Christmas, what makes it special, is the Incarnation. A mystery is not part of our human, rational understanding. It is sublime, and part of divine revelation. Non-Christians can witness the events of Christmas—the baby in the manger, etc.—but without God’s revelation, their understanding is limited to the empirical and rational experience of the season. Only with the touch of God is the mystery of the Incarnation opened. It transcends what we can know.

The child Jesus is a sign. Isaiah prophesied, “Therefore, the LORD himself will give you a sign: The virgin will be with child and will give birth to a son and will call him Immanuel” (Is. 8:14), that is, God with us. Isaiah’s prophesy what that a child would signify that the word of the Lord that Israel would not be destroyed by its enemies was true. Jesus came as a sign to show all men that despite the appearances of death and destruction, God is victorious, and He triumphs. Not only is the Christ Child a sign, He is the thing signified. He is the victory over death; He is triumph. And so, John opens his Gospel.

John 1:1–2. God is eternal, from before time. He always was, always is, and always shall be. YHWH. “‘I am the Alpha and the Omega,’ says the Lord God, ‘who is, and who was, and who is to come, the Almighty’” (Rev. 1:8). The Word was with God in the beginning, before creation began; there was never a time that the Word was not.

John 1:3. God created everything. This sounds obvious, doesn’t it? But our advanced, modern culture has, through the miracles of science, largely abandoned this belief. Yet science shows that this universe in it earliest moments was a point—that it had an origin and start. Some scientists postulate that there was a former state from which our universe’s earliest moments began, but this chain of causality only points to a single, primordial mover, the first cause, the originator.

John 1:4. God is life, and He is the light of men. Jesus said, “I am the Living One; I was dead, and behold I am alive for ever and ever. I hold the keys of death and Hades” (Rev. 1:18. Jesus, rising from the grave, proved that His power is that of life, life that exceeds the seemingly unbreakable grip of death. Jesus said, “I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life” (Jn. 8:12).

John 1:5. Men did not understand the light, hence the life, of God. Another translation of “understand” is “overcome,” and John’s Gospel is sufficiently rich to assume that he meant both nuances. The darkness does not “understand” the light, because it cannot perceive the meaning of it. Light wipes darkness away, so there can be no knowing. Also, darkness cannot overcome light. Evil (darkness) is parasitic; it corrupts good, but it cannot exist without a good to corrupt. But good (light) has existence of itself. For example, is moldy bread good or bad? It’s bad. But the mold has no existence apart from the bread. The true light is the true bread come down from heaven, that never molds or spoils or goes stale, but is always fresh.

John 1:6–9. God sent a messenger, John, to bear witness to the light: “The true light that gives light to every man was coming into the world” (Jn. 1:9). God doesn’t fail to announce His plans. So God sent a witness ahead of the Word, so that men might believe. God was setting man up to succeed. At every turn, the Father prepares the way for His children to return to Him. But each child must decide whether or not to accept the Father’s offer. Our family sees this poignantly in my brother. My father would pay every expense for him to move to Maryland, and would let him live with them without paying rent or food, so much does my father long to have his son with him. But my brother does not want to move. And so, he remains in Hawaii.

John 1:10–11. The Word (true light) was in the world, but not recognized, or received. God made the world, and it is His. He represented Himself in the Old Testament time, through Noah, Abraham, Moses, Elijah, Isaiah, David, Solomon, and more, but He was not accepted. He offered Himself in the Gospel times, and was arrested, convicted, mocked, scourged, blasphemed, and killed. Man could have rejected Jesus in no more complete way. At the cross, the people mocked in summary His entire ministry: “He saved others; let him save himself if he is the Christ of God, the Chosen One” (Lk. 23:35). But not everyone rejected Him.

John 1:12–13. To all who received Him, the Word (true light) gave the right to become children of God beyond natural, human power. We who accept Christ Jesus have no power ourselves to become children of God, but we can tap His power. New life apart from Christ, and apart from His Body the Church, is impossible. Jesus has the light of life; He gives water that wells up to eternal life (Jn. 4:14); He gives life to those whom He pleases (5:21); He has life in Himself (5:26); He is the bread of life (6:48); He is the resurrection and the life (11:25); He is the way, the truth, and the life (14:6). Earthly life ends at death, and then begins the eternal death. But spiritual life does not run out, but continues and increases at death. This is the gift the Father offers. That’s the gift of Christ as Christmas.

John 1:14. The Word, God himself, became flesh.

In the Nicene Creed we say that Christ came down: “For us men and for our salvation.” He came not for plants, animals, or the earth. He did not come for the angels. Jesus came for “us men.” God, who had made man in His own image and likeness, now became man and took on the likeness of what He created. God took on our likeness, to restore it to His own once more. Jesus Christ humbled himself to share in our humanity, so that we could display the divine image.

So the Word became flesh. The Word, which is God all-powerful, became flesh. "Kai ho logos sarx egeneto." Flesh, sara, is the same word translated “sinful nature.” Listen to John’s force. The Word, God most holy, became flesh, took on our weakened nature. “For what the law was powerless to do in that it was weakened by the sinful nature (sarj, flesh), God did by sending his own Son in the likeness of sinful nature to be a sin offering” (Rom. 8:3). “God made him who had no sin to become sin for us, so that in him we might become the righteousness of God” (2 Cor. 5:21).

In seminary we were told that sermons had to have an application. The application of the sermon is this: Hold onto the Mystery of Christmas, the Incarnation, the Word made flesh. Don't let it fall away. It is the sine qua non of Christianity, that without which it is not. A mediator must represent both parties, and Christ is our only Mediator and Advocate.

This is the Gospel of Christmas: the Word became flesh, God became man. The world wants to neuter Christ and make Him a teacher, or prophet, anything except for the Word made flesh. St. Paul writes, “But even if we or an angel from heaven should preach a gospel other than the one we preached to you, let him be eternally condemned! As we have already said, so now I say again: If anybody is preaching to you a gospel other than what you accepted, let him be eternally condemned” (Gal. 1:8–9). Hold fast to the true Gospel, saints.