But the most remarkable thing is this. Whenever you find a man who says he does not believe in a real Right and Wrong, you will find the same man going back on this a moment later. He may break his promise to you, but if you try breaking one to him he will be complaining ‘It’s not fair’ before you can say Jack Robinson.

Lewis, C. S.. Mere Christianity (C.S. Lewis Signature Classics) (p. 6). HarperCollins. Kindle Edition.