I have a post on the humanity of Jesus up at the True Woman blog this morning.
That Jesus “increased in wisdom and in stature” (Luke 2:52) is evidence that he was truly human. In the incarnation, the Eternal Son, who is the second person of the Trinity, was joined forever with genuine human nature, so that Jesus was (and is) fully God and fully human in one person.
If you’re left wondering how that works, you’re not alone. The ancient Christians took the biblical data and developed creeds outlining some things we can know about Christ’s nature, but there is much they don’t and can’t explain. J. I. Packer calls this a “marvelous mystery”—and he’s right!