Genesis 20:2
1 Abraham journeyed from there to the Negev region and settled between Kadesh and Shur. While he lived as a temporary resident in Gerar, 2 Abraham said about his wife Sarah, “She is my sister.” So Abimelech, king of Gerar, sent for Sarah and took her. 3 But God appeared to Abimelech in a dream at night and said to him, “You are as good as dead because of the woman you have taken, for she is someone else’s wife.”
LXX Genesis 20:2
1 And from there Abraam moved to the land toward the southwest and lived between Kades and between Sour and resided in Gerara as an alien. 2 And Abraam said of his wife Sarra, “She is my sister,” for he was afraid to say, “She is my wife,” lest perhaps the men of the city kill him on her account. Then Abimelech king of Gerara sent and took Sarra. 3 And God came in to Abimelech in hisc sleep during the night and said, “Look, you are about to die by reason of the woman whom you have taken, whereas she is married to a man.”
Notes and References
"... scholars believed that the translation (LXX Genesis) was made from a text close to Masoretic text... “These Notes are also based on the presupposition that the parent text being translated was in the main much like the consonantal text of the Masoretic text.” Likewise, Wevers ascribed the long addition in LXX Genesis 20:2 to the translator: “Once again it illustrates the intelligent approach Genesis took in interpreting his parent text; the text simply had to make sense” ..."
Tov, Emanuel Textual Criticism of the Hebrew Bible, Qumran, Septuagint: Collected Essays (p. 170) Brill, 2015