The incarnation refers literally to the in-fleshing of the eternal Son of God — Jesus “putting on our flesh and blood” and becoming fully human. The doctrine of the incarnation claims that the eternal second person of the Trinity took on humanity in the person of Jesus of Nazareth. A helpful way to remember the key aspects of the incarnation is the summary statement of John 1:14: “The Word became flesh.”
The Word refers to the eternal divine Son who was “in the beginning with God” and who himself is God (John 1:1). From eternity past until he took on humanity, the Son of God existed in perfect love, joy, and harmony in the fellowship of the Trinity. Like the Father and the Spirit, he was spirit and had no material substance. But at the incarnation, the eternal Word entered into creation as human. He became a first-century Jew.
Became does not mean that he ceased to be God. In becoming man, he did not forsake his divine nature, as if that were even an option. Rather, he became man by taking on human nature in addition to his divine nature. It is essential to the incarnation — and very helpful throughout all theology — to recognize that divinity and humanity are not mutually exclusive. The Son of God didn’t have to pick between being God and being man. He could be both at the same time. The eternal Word became human.
Flesh isn’t merely a reference to the human body but the entirety of what makes up humanity — body, mind, emotions, and will. Hebrews 2:17 and 4:15 teach that to save human beings Jesus had to be made like us “in every respect” except our sin. In the incarnation, everything proper to humanity was united to the Son of God. The Son of God did not only become like man; he actually became truly and fully human.
The Word Became Flesh
So the eternal Son of God, without ceasing to be God, took on a fully human nature. This is what Christians have long called “the incarnation.”
And what a magnificent truth and fuel for worship this is. Jesus didn’t just become man because he could. This was no circus stunt, just for show. He became man, in the world of the ancient creed, “for us and for our salvation.” The eternal Word became frail human flesh and blood to save us from our sin and to free us to marvel at and enjoy the unique union of divinity and humanity in his one spectacular person.
The incarnation is not only the way in which Jesus became Immanuel — God with us — but it’s an eternal testimony that he and his Father are unswervingly for us.