What does Genesis 20:12 mean?
Abraham continues to answer Abimelech's questions about why he lied about Sarah being his sister (Genesis 20:9). Now he reveals that it's not completely a lie. She is his half-sister, as well as being his wife. They share the same father and different mothers. Of course, even true statements, told with the intent to deceive and to disguise some other important truth, are still lies. Abraham was acting in fear for his own life, and he knew full well what he was doing.Though God, in the Law of Moses, would later forbid marriage for those in that closeness of family, it was apparently not uncommon or disapproved of in Abraham's day. God never seems to have condemned Abraham or Sarah for it, either. In contrast, the relations between Lot and his daughters described in the previous chapter was apparently thought to be wrong both in Abraham's time and, later, under the Law of Moses.