Genesis 26:8-10

After Isaac had been there a long time, Abimelech king of the Philistines happened to look out a window and observed Isaac caressing his wife Rebekah. So Abimelech summoned Isaac and said, “She is really your wife! Why did you say, ‘She is my sister’?” Isaac replied, “Because I thought someone might kill me to get her.” Then Abimelech exclaimed, “What in the world have you done to us? One of the men might easily have had sexual relations with your wife, and you would have brought guilt on us!”