It is not Jesus’ birth which is so remarkable but His conception. When the angel announced that although she was a virgin, Mary would have a baby who would rule the entire universe, she simply asked the sensible question: “How?” And with that question we arrive at the very heart of the Christian story.

How was this child to be conceived? God was going to make it happen. He would do it. The language of being “overshadowed” reminds us of God’s divine presence being symbolized to the Israelites by a great cloud (Exodus 40:34-38). The conception, in other words, would be supernatural, able to be accomplished by God alone.

As Paul worked through the theology of the incarnation, he wrote, “When the fullness of time had come, God sent forth his Son, born of woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons” (Galatians 4:4-5). He emphasized that the Redeemer had to be human so that He would be of the same nature as those whom He came to save: a man dying for mankind. But it was equally imperative that the Redeemer should be perfectly holy, because no sinful person could effect atonement for the sins of others. He had to be Immanuel—God with us—and He had to be man.

The early Christians hammered out the incarnation’s implications and came up with ways to describe the one who was conceived by the Spirit in Mary’s womb, coming to the convictions that have passed down to us in the early creeds. Our spiritual forefathers identified the wonder of the incarnation, bowed before the mystery of it, and affirmed that Jesus was, and remains, very God and very man.

The idea that God would supernaturally invade this world shouldn’t surprise or discomfort us. It takes a supernatural invasion of God into individuals’ lives, after all, to bring them to living faith, just as God sovereignly worked a miracle in Mary’s womb in order to bring us the Redeemer. Jesus told Nicodemus that unless someone is born from above—a birth brought about by God through His Spirit—they would not see God’s kingdom (John 3:3). If we have been brought to salvation, it is only because God has done it. You did no more to save yourself than Mary did to become pregnant with your Savior. The “How?” of salvation is always answered only by “God did it.”

So, bow today before the wonder and mystery of God taking on flesh. And bow today before the wonder and mystery of God redeeming you. For that, no less than the virgin birth of the Son of God, is the supernatural work of God.