Amnon is infatuated with his half-sister Tamar and Jonadab advises him to act. We need to avoid anything that will encourage us to act on evil desires. Amnon rapes Tamar and then hates her. According to the law, he was obligated to marry her and pay a financial penalty. David is angry but the text doesn’t tell us that he did anything about it; perhaps paralyzed by his own sexual immorality. If parents set a bad example, children will feel free to commit the same sins. There is grace for victims and sinners in Christ. In Jesus’ sight they are pure and clean.