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.

Said he not himself unto me, She is my sister? and she, even she herself said, He is my brother: in the integrity of my heart and the innocency of my hands have I done this.

And moreover she is indeed my sister, the daughter of my father, but not the daughter of my mother; and she became my wife: and it came to pass, when God caused me to wander from my father’s house, that I said unto her, This is thy kindness which thou shalt show unto me: at every place whither we shall come, say of me, He is my brother.