|Why and how would you reject this Jesus?|
But I cannot apply to divine matters a method of exegesis which I have already rejected with contempt in my profane studies. Any theory which bases itself on a supposed "historical Jesus" to be dug out of the Gospels and then set up in opposition to Christian teaching is suspect. There have been too many historical Jesuses - a liberal Jesus, a pneumatic Jesus, a Barthian Jesus, a Marxist Jesus. They are the cheap crop of each publisher's list, like the new Napoleons and new Queen Victorias. It is not to such phantoms that I look for my faith and my salvation.
-- from "Why I am not a Pacifist" by C. S. Lewis (p. 88, The Weight of Glory)
I hope, by this quote, people wouldn't misunderstand and think the historical Jesus is actually to be rejected. It is what we may in our days call, the reconstruction of historical Jesus that we must reject. It is the biblical Jesus, that is also the real historical Jesus we must embrace for our faith and salvation.
As a side note, it is interesting that, while Lewis himself had some theological problems, he doesn't seem to have had much patience for Barth.