Robert G. Ingersoll Quote

All inspired books, teaching that what the supernatural commands is right, and right because commanded, and that what the supernatural prohibits is wrong, and wrong because prohibited, are absurdly unphilosophic. And all inspired books, teaching that only those who obey the commands of the supernatural are, or can be, truly virtuous, and that unquestioning faith will be rewarded with eternal joy, are grossly immoral. Again I say: Intelligence is the only moral guide.

What Would You Substitute for the Bible as a Moral Guide? (1900)