Genesis 12:13
11 As he approached Egypt, he said to his wife Sarai, “Look, I know that you are a beautiful woman. 12 When the Egyptians see you they will say, ‘This is his wife.’ Then they will kill me but will keep you alive. 13 So tell them you are my sister so that it may go well for me because of you and my life will be spared on account of you.” 14 When Abram entered Egypt, the Egyptians saw that the woman was very beautiful. 15 When Pharaoh’s officials saw her, they praised her to Pharaoh. So Abram’s wife was taken into the household of Pharaoh,
Genesis 26:7
5 All this will come to pass because Abraham obeyed me and kept my charge, my commandments, my statutes, and my laws.” 6 So Isaac settled in Gerar. 7 When the men of that place asked him about his wife, he replied, “She is my sister.” He was afraid to say, “She is my wife,” for he thought to himself, “The men of this place will kill me to get Rebekah because she is very beautiful.” 8 After Isaac had been there a long time, Abimelech king of the Philistines happened to look out a window and observed Isaac caressing his wife Rebekah. 9 So Abimelech summoned Isaac and said, “She is really your wife! Why did you say, ‘She is my sister’?” Isaac replied, “Because I thought someone might kill me to get her.”
Notes and References
"... Abram and Sarai did not behave like the beneficiaries and heralds of YHWH’s blessings (Genesis 12:2–3), neither is their life story comparable with the ill-treated Hebrew slaves that desperately cried for a change (Exodus 2:23). Interpreters of the Hellenistic and later periods were careful to circumnavigate and/or sugarcoat the essence of the story that portrays Abram and Sarai as a worried, but shrewd couple. The euphemizing of Abram’s experience in Egypt in the Genesis Apocryphon “presupposes a form of Genesis at least akin to our major versions (LXX, Masoretic, Samaritan), which was venerated enough to warrant an interpretative rewriting” (Machiela 2009, 131). Moreover, the linguistic features of Genesis 12 do not support a post-exilic dating of the passage (Hendel and Joosten 2018, 38–39; compare Polak 2016). Finally, the prophets of the (late) pre-exilic, exilic, and post-exilic periods strongly opposed any suggestion of seeking help in Egypt, let alone the idea that pharaoh would embody a sincere man of high moral standing. Another critical point regards the fact that Abram was married to his half-sister, which is at odds with the Torah ... (Compare Genesis 12:13; 20:12; and 26:7; with Leviticus 18:9 and Deuteronomy 27:22. There is one more incident where a man is married to his half- sister, Exodus 6:20; 2 Samuel 13:12 only mentions this as a possible option) ..."
Heide, Martin, and Joris Peters Camels in the Biblical World (p. 205) Eisenbrauns, 2021