Genesis 26:8-9

One day, after they had been there quite a long time, Abimelech, king of the Philistines, looked out his window and saw Isaac fondling his wife Rebekah. Abimelech sent for Isaac and said, “So, she’s your wife. Why did you tell us ‘She’s my sister’?” Isaac said, “Because I thought I might get killed by someone who wanted her.”