Genesis 20:12-13

12Besides, she actually is my sister, the daughter of my father, but not the daughter of my mother; and she became my wife;

13and it came about, when 1God caused me to wander from my father’s house, that I said to her, ‘This is 2the kindness which you will show to me: 3everywhere we go, 4say of me, “He is my brother.”’”