A Christian understanding of the nature and life of the Church is profoundly shaped by consideration of the existence of Jesus Christ, who is both fully God and has a fully human body. We need venture no further than that word – body – to begin to grasp the momentous mystery of the Church, the body and bride of Christ. As we are told in the Holy Scriptures, Christ became one flesh with His Church (Eph. 5: 31-32). Without the great and unparalleled miracle of the Incarnation, the Church cannot be who she actually is: the body of Christ.

It is not uncommon for modern Christians to think of the incarnation of our Lord as not much more than a necessary prerequisite, or precondition, for his atoning death. There is no doubt that the crucifixion and death of Christ would have been powerless had He not been truly and fully human. But there is indeed more we can, and should, say about the atoning implications of the incarnation. For, when God became incarnate He began a comprehensively astounding work of reconciliation that healed and saved every last aspect of our fallen humanity, from cradle to grave.

When the eternal Word and Son of God “became flesh and dwelt among us” (John 1:14), God decided in his omnipotent freedom to become who we are, without ever ceasing to be fully who He has always been, and always will be. In the miracle of Christmas, God became a fully human being in swaddling clothes, even as He remained the Lord of the universe. When God the Son became incarnate he entered into the deepest ground of our human existence, to forever live his divine life in our human nature. He did this in order to grant us a life-giving, life-transforming share in His communion with the Father through the Holy Spirit, the glorious first-fruits of his reconciling all things in heaven and earth in Himself (Eph. 1:10; Col. 1:20). The nineteenth century Reformed theologian and churchman John Williamson Nevin thus exclaims:

“The Word became flesh!” In this simple, but sublime enunciation, we have the whole gospel comprehended in a word … The incarnation is the key that unlocks the sense of all God’s revelations. It is the key that unlocks the sense of all God’s work’s, and brings to light the true meaning of the universe … The incarnation forms thus the great central fact of the world.