Genesis 26:8-9

It happened when he had been there a long time, that Abimelech king of the Philistines looked out of a window and saw Isaac caressing Rebekah his wife. Then Abimelech called Isaac and said, “See here, Rebekah is in fact your wife! How did you [dare to] say to me, ‘She is my sister’?” And Isaac said to him, “Because I thought I might be killed because of her [desirability].”