2 Samuel 13:13

as one of the fools in Israel "Fool" denotes not merely one who is stupid and ignorant, but one who has abandoned the fear of God, and cast off the restraints of decency and morality. Cp. ch. 2 Samuel 3:33; Psalms 14:1. "Folly" is a term specially applied to unchastity.

he will not withhold me from thee The marriage of half-brothers and sisters was permitted in patriarchal times, as is shewn by the example of Abraham and Sarah (Genesis 20:12), but was expressly forbidden by the Mosaic law. Either the law was not strictly observed at this time, or Tamar, hoping to escape immediate violence, suggested that the king had a dispensing power, and might permit a regular marriage.