A fine and accessible book on the subject is Why Bother Being Good? The Place of God in the Moral Life, by John Hare, professor of philosophy at Calvin College. He is one of the most important Christian moral philosophers writing today (see The Moral Gap and God's Call). He argues powerfully that morality does need God. His point is not that a person who doesn't believe in God can't be good-there are many such people, and some of them live lives worthy of saints.
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