Milcah was a woman of ancient Mesopotamia and an ancestor of the patriarch Jacob. Milcah was born to Haran, who had another daughter, Iscah. The Jewish Encyclopedia states that this is the Haran who died in Ur, the brother of Abraham, and father of Lot; but notes Ibn Ezra's commentary on Gen. 11:29 which indicates that Haran, Milcah's father, was a different person from Haran, Abraham's brother. Milcah married Abraham's brother Nahor. (Gen. 11:29.)
In the Babylonian Talmud, Rabbi Isaac presumes that the two men with the name Haran are one person. If that is true, then Milcah married to her uncle. Although Leviticus would later outlaw marriages between aunt and nephew (Lev. 18:14, 20:19), it did not rule out marriage between uncle and niece. (See, e.g., Gunther Plaut, The Torah: a Modern Commentary, 881. New York: UAHC, 1981.) The Talmud approved of a man who married his sister’s daughter. (Yevamot 62b-63a.) And in the Talmud, Rabbi Isaac equates Milcah’s sister Iscah with Sarah (then Sarai), who married Abraham (then Abram), who was also their uncle. (Sanhedrin 69b.) Thus, according to Rabbi Isaac, the two sisters, Milcah and Iscah, married the two brothers, Nahor and Abraham.
Milcah and Nahor had eight children, Uz, Buz, Kemuel, Chesed, Hazo, Pildash, Jidlaph, and Bethuel. (Gen. 22:21.) Targum Jonathan says that Providence granted Milcah conception in the merit of her sister Sarah. (Targum Jonathan to Gen. 22:20.) Nahor also had four children by his concubine, Reumah. (Gen. 22:24.)
Milcah’s son Bethuel moved to Padan-aram and fathered Rebekah. (Gen. 22:23; 24:15, 24, 47.) Milcah’s granddaughter Rebekah then married Milcah’s nephew Isaac (Gen. 24:67; 25:20), and gave birth to Jacob (Gen. 25:21–26), who became Israel. (Gen. 32:28; 35:10. According to a Midrash, Milcah was the forbearer of all the prophets in the world. (Yalkut Shimoni Balak 22:20.)