First drafts are for learning what your novel or story is about. Revision is working with that knowledge to enlarge and enhance an idea, to re-form it. D.H. Lawrence, for instance, did seven or eight drafts of The Rainbow. The first draft of a book is the most uncertain—where you need guts, the ability to accept the imperfect until it is better. Revision is one of the true pleasures of writing.
From Bernard Malamud, “The Writer at Work” (1974); reproduced in Alan Cheuse & Nicholas Delbanco, eds., Talking Horse: Bernard Malamud on Life and Work (1996).