Genesis 26:9-10

9Then Abimelech called Isaac and said, “Behold, she certainly is your wife! So how is it that you said, ‘She is my sister’?” And Isaac said to him, “Because I thought, ‘otherwise I might be killed on account of her.’”

10And 1Abimelech said, “What is this that you have done to us? One of the people might easily have slept with your wife, and you would have brought guilt upon us.”