"For Christianity is a fighting religion. It thinks God made the world -- that space and time, heat and cold, and all the colours and tastes, and all the animals and vegetables, are things that God 'made up out of His head' as a man makes up a story. But it also thinks that a great many things have gone wrong with the world that God made and that God insists, and insists very loudly, on our putting them right again.
--from Mere Christianity
as quoted in A Year with C. S. Lewis: Daily Readings from His Classic Works