There is no Christianity without the Incarnation. Moreover, the Incarnation is not some vague notion of the divine identifying with the human. It is relentlessly concrete: the Word that was with God and that was God became flesh (as John writes elsewhere, 1:1, 14 in the gospel of John). That is fundamental in John’s day, when he is combating those who presuppose that what is truly spiritual might don human flesh but could not become a human being; it is fundamental today, when we might be combating a philosophical naturalist who insists that the only reality is what occupies the continuum of space and time.
Carson, D. A. (1998). For the love of God : A daily companion for discovering the riches of God’s Word. Volume 1 (December 2). Wheaton, Ill.: Crossway Books.