In Gen. 20:12 Abram speaks of Sarai as his half-sister, the daughter of the same father, but not the same mother. The common Jewish tradition referred to by Josephus (Antiquities 1,6,6) and also by Jerome, is that Sarai was identical with Iscah (see Gen. 11:29), daughter of Haran and sister of Lot, who is called Abraham's "brother."
