Genesis 12:11-13. NIV

11 As he was about to enter Egypt, he said to his wife Sarai, “I know what a beautiful woman you are. 12 When the Egyptians see you, they will say, ‘This is his wife.’ Then they will kill me but will let you live. 13 Say you are my sister, so that I will be treated well for your sake and my life will be spared because of you.”