C.S. Lewis on Ethics and Christianity
God in the Dock (Grand Rapids, Michigan: Eerdmans, 1970)
Christianity claims to give an account of facts — to tell you what the real universe is like. Its account of the universe may be true, or it may not, and once the question is really before you, then your natural inquisitivenes must make you want to answer. If Christianity is untrue, then no honest man will want to believe it, however helpful it might be: if it is true, every honest man will want to believe it, even if it gives him no help at all. As soon as we have realized this, we realise something else. If Christianity should happen to be true, then it is quite impossible that those who know this truth and those who don't should be equally well-equipped for leading a good life. Knowledge of the facts must make a difference to one's actions.