Genesis 20:9-12

9Then Abimelech called Abraham in and said to him, “What have you done to us? How did I sin against you that you have brought such enormous guilt on me and on my kingdom? You have done things to me that should never be done.”

10Abimelech also asked Abraham, “What made you do this?”

11Abraham replied, “I thought, ‘There is absolutely no fear of God in this place. They will kill me because of my wife.’

12Besides, she really is my sister, the daughter of my father though not the daughter of my mother, and she became my wife.