Genesis 26:7-9

7The men of Gerar asked Isaac about his wife. He told them, ‘She is my sister.’ He was afraid to say, ‘She is my wife.’ He thought that the men of Gerar might kill him because Rebekah was very beautiful.

8Isaac stayed in Gerar for a long time. One day Abimelech, the king of the Philistines, looked down from his window. He saw that Isaac was kissing Rebekah.

9Abimelech called Isaac to come to him. He said, ‘Rebekah is your wife! Why did you say, “She is my sister”?’ Isaac replied, ‘I thought that someone might kill me because of her.’