3 But Amnon had a friend whose name was Jonadab, the son of Shimeah, David's brother: and Jonadab was a very wise man. 4 And he said to him, O son of the king, why are you getting thinner day by day? will you not say what your trouble is? And Amnon said to him, I am in love with Tamar, my brother Absalom's sister. 5 Then Jonadab said to him, Go to your bed, and let it seem that you are ill: and when your father comes to see you, say to him, Let my sister Tamar come and give me bread, and get the food ready before my eyes, so that I may see it and take it from her hand. 6 So Amnon went to bed and made himself seem ill: and when the king came to see him, Amnon said to the king, Please let my sister Tamar come and make me one or two cakes before my eyes, so that I may take food from her hand.
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.