Genesis 20:2, 5, 12-13

And Abraham said of Sarah his wife, “She is my sister.” And Abimelech king of Gerar sent and took Sarah.

Did he not himself say to me, ‘She is my sister’? And she herself said, ‘He is my brother.’ In the integrity of my heart and the innocence of my hands I have done this.”

Besides, she is indeed my sister, the daughter of my father though not the daughter of my mother, and she became my wife. And when God caused me to wander from my father’s house, I said to her, ‘This is the kindness you must do me: at every place to which we come, say of me, “He is my brother.”’”