“We are told that Christ was killed for us, that His death has washed out our sins, and that by dying He has disabled death itself. That is the formula. That is Christianity. That is what has to be believed. Any theories we build up as to how Christ's death did all this are, in my view, quite secondary: mere plans or diagrams to be left alone if they do not help us, and, if they do help us, not to be confused with the thing itself.”