“The moment you have a self at all, there is a possibility of putting yourself first—wanting to be the centre—wanting to be God, in fact. That was the sin of Satan: and that was the sin he taught the human race. Some people think the fall of man had something to do with sex, but that is a mistake. (The story in the Book of Genesis rather suggests that some corruption in our sexual nature followed the fall and was its result, not its cause.) What Satan put into the heads of our remote ancestors was the idea that they could ‘be like gods’—could set up on their own as if they had created themselves—be their own masters—invent some sort of happiness for themselves outside God, apart from God. And out of that hopeless attempt has come nearly all that we call human history—money, poverty, ambition, war, prostitution, classes, empires, slavery—the long terrible story of man trying to find something other than God which will make him happy.
The reason why it can never succeed is this. God made us: invented us as a man invents an engine. A car is made to run on petrol, and it would not run properly on anything else. Now God designed the human machine to run on Himself. He Himself is the fuel our spirits were designed to burn, or the food our spirits were designed to feed on. There is no other. That is why it is just no good asking God to make us happy in our own way without bothering about religion. God cannot give us a happiness and peace apart from Himself, because it is not there. There is no such thing.”
—C. S. Lewis, Mere Christianity (HarperOne, 1980), pp. 49–50.