2 Samuel — Chapter 13

Amnon loved his half-sister Tamar with a sick passion. Lapide notes the medical diagnosis of amor aegrotus (the sickness of love) from Aristotle; the story of Antiochus and Stratonice is cited by Lapide as a pagan parallel. He interprets Amnon's subsequent hatred as the natural result of disordered passion spending itself.

And being stronger, he forced her. Lapide: God permitted David's firstborn son to commit this sin to chastise David's own adultery — \"Let parents be chaste so that by example rather than words they teach chastity to their sons. If they are unchaste, their children will imitate their unchastity.\"