Genesis 20:10-13

10And Abimelech said unto Abraham, What sawest thou, that thou hast done this thing?

11And Abraham said, Because I thought, Surely the fear of God is not in this place; and they will slay me for my wife’s sake.

12And yet indeed she is my sister; she is the daughter of my father, but not the daughter of my mother; and she became my wife.

13And 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 shew unto me; at every place whither we shall come, say of me, He is my brother.