Abimelech sent for Isaac and said, "So she is really your wife! How could you say, 'She is my sister'?" Isaac replied, "Because I thought I might die on account of her."

Genesis 26:8
When Isaac had been there a long time, Abimelech king of the Philistines looked down from the window and was surprised to see Isaac caressing his wife Rebekah.

Genesis 26:10
"What is this you have done to us?" asked Abimelech. "One of the people could easily have slept with your wife, and you would have brought guilt upon us."

And Abimelech called Isaac, and said, Behold, of a surety she is your wife; and how said you, She is my sister? And Isaac said to him, Because I said, Lest I die for her.