God the Son, the second person of the Trinity (from the Incarnation forward), is one person with two natures: the divine nature (Theos) fully God, and the human nature (anthropos) fully human (as Adam was before the fall, yet without a sin nature).

Thus, in His divine nature, there is no sense in which God is God that the Son has not also always been God (the Son is co-eternal), and there is no sense in which Adam was a man before the fall that Jesus did not also become a man.

Thus, in His Deity He can be “the same yesterday, today, and forever” (Hebrew 13:8), and yet in His humanity He “increased in wisdom and stature and in favor with God and with people” (Luke 2:52).

He truly was God, and that “No one has seen God. The One and Only Son . . . has revealed Him” (John 1:18, HCSB).

As C.S. Lewis argued, “A man who . . . said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic—on the level with the man who says he is a poached egg—or else he would be the Devil of Hell. . . . Either this man was, and is, the Son of God: or else a madman. . . . You can shut Him up for a fool . . . or you can fall at His feet and call Him Lord and God. But let us not come with any patronizing nonsense about His being a great human teacher. He has not left that open to us” (Mere Christianity).