God is the gasoline

Lewis makes a great analogy in Mere Christianity. He states that God made us, like we made automobiles. We designed cars to run on gasoline (or diesel). God designed us 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". Lewis points out that when we try to make ourselves happy in any other way we are doomed to failure. We can't get true happiness apart from God. God is the gasoline that makes us go.