Genesis 11:29

Abram and Nahor took them wives. Nahor’s wife, Milcah, was a daughter of his brother Haran and therefore his own niece. Abram’s wife, Sarai, was his half sister, a daughter of Terah by another wife than Abram’s mother (see ch. 20:12). Marriage with a half sister, and with other close relatives, was afterward forbidden by the Mosaic civil code, though apparently still permitted in Abram’s time (see Lev. 18:6, 9, 14).

Iscah. It is not clear why Iscah, another daughter of Haran, is mentioned here. Following an old Jewish tradition, some commentators have seen the name as another name of Sarai, Abram’s wife. Others think she was the wife of Lot. There is no factual basis for any such suppositions.