Genesis 26:7-8, 10

When the men who lived there asked Isaac about his wife, Rebekah, he said, “She is my sister.” He was afraid to say, “She is my wife.” He thought, “They will kill me to get her, because she is so beautiful.” But some time later, Abimelech, king of the Philistines, looked out his window and saw Isaac caressing Rebekah.

“How could you do this to us?” Abimelech exclaimed. “One of my people might easily have taken your wife and slept with her, and you would have made us guilty of great sin.”