Wife-sister narratives in Genesis

There are three wife-sister narratives in Genesis, part of the Torah, all of which are strikingly similar. The narratives occur in Genesis 12, 20 and 26. At the core of each is the story of a Biblical Patriarch, who has come to be in the land of a powerful foreign overlord who misidentifies the Patriarch's wife as the Patriarch's sister, and consequently attempts to wed her himself. The overlord later finds out his error. Two of the three stories are similar in many other details, including the ruler's name, Abimelech.

The first episode appears in Genesis 12:10-20.

Abram (later called Abraham) is pressured to move to Egypt in order to evade a famine. Because his wife (also his half-sister), Sarai, is very beautiful, Abram asks her to say that she was only his sister lest the Egyptians kill him so that they can take her. On arriving before the Pharaoh, the Egyptians recognise Sarai's beauty, and the Egyptian princes shower Abram with gifts of livestock and servants to gain her hand in marriage. Sarai thus becomes part of "Pharaoh's house", but God sends a plague. Pharaoh restores Sarai to Abram and orders them to leave Egypt with all the possessions Abram had acquired in Egypt.

Genesis 20:1-16 narrates the story of Abraham emigrating to the southern region of Gerar, whose king is named Abimelech. Abraham states that Sarah, his wife, is really his sister, leading Abimelech to try to take Sarah as a wife; however, God intervened before Abimelech touched Sarah. Abimelech complains to Abraham, who states that Sarah is his half-sister.

Abimelech then restores Sarah to Abraham, and gives him gifts of livestock and servants by way of apology, and also allows Abraham to reside anywhere in Gerar. Abimelech also gives 1000 pieces of silver to Abraham to reprove Sarah by a "covering of the eyes". Abraham then prays for Abimelech and the king and his wife and concubines are able to conceive children; they previously could not.

...
Wikipedia