Genesis 12:11-13

And when he was about to enter Egypt, he said to Sarai his wife, “Listen: I know that you are a beautiful woman; so when the Egyptians see you, they will say, ‘This is his wife’; and they will kill me [to acquire you], but they will let you live. Please tell them that you are my sister so that things will go well for me for your sake, and my life will be spared because of you.”