" some believers took the Christological views of the Gospel to an extreme and maintained that Jesus was so much God that he could not really have been a man. The book 1 John was written, then, to counter that view by insisting that 'Jesus Christ came in the flesh' and that anyone who refused to acknowledge his fleshly existence was in fact an antichrist. "
― Bart D. Ehrman , How Jesus Became God: The Exaltation of a Jewish Preacher from Galilee