3 Amnon had a good friend, Jonadab, the son of David's brother Shimeah. Jonadab was exceptionally streetwise. 4 He said to Amnon, "Why are you moping around like this, day after day - you, the son of the king! Tell me what's eating at you." "In a word, Tamar," said Amnon. "My brother Absalom's sister. I'm in love with her." 5 "Here's what you do," said Jonadab. "Go to bed and pretend you're sick. When your father comes to visit you, say, 'Have my sister Tamar come and prepare some supper for me here where I can watch her and she can feed me.'" 6 So Amnon took to his bed and acted sick. When the king came to visit, Amnon said, "Would you do me a favor? Have my sister Tamar come and make some nourishing dumplings here where I can watch her and be fed by her."
Matthew Henry's Commentary on 2 Samuel 13:3-6
Commentary on 2 Samuel 13:1-20
(Read 2 Samuel 13:1-20)
From henceforward David was followed with one trouble after another. Adultery and murder were David's sins, the like sins among his children were the beginnings of his punishment: he was too indulgent to his children. Thus David might trace the sins of his children to his own misconduct, which must have made the anguish of the chastisement worse. Let no one ever expect good treatment from those who are capable of attempting their seduction; but it is better to suffer the greatest wrong than to commit the least sin.