28 Absalom commanded his servants, saying, “Mark now, when Amnon’s heart is merry with wine; and when I tell you, ‘Strike Amnon,’ then kill him. Don’t be afraid. Haven’t I commanded you? Be courageous, and be valiant!” 29 The servants of Absalom did to Amnon as Absalom had commanded. Then all the king’s sons arose, and every man got him up on his mule, and fled.
30 It happened, while they were in the way, that the news came to David, saying, “Absalom has slain all the king’s sons, and there is not one of them left!” 31 Then the king arose, and tore his garments, and lay on the earth; and all his servants stood by with their clothes torn. 32 Jonadab, the son of Shimeah, David’s brother, answered, “Don’t let my lord suppose that they have killed all the young men the king’s sons; for Amnon only is dead; for by the appointment of Absalom this has been determined from the day that he forced his sister Tamar. 33 Now therefore don’t let my lord the king take the thing to his heart, to think that all the king’s sons are dead; for Amnon only is dead.” 34 But Absalom fled. The young man who kept the watch lifted up his eyes, and looked, and behold, many people were coming by way of the hillside behind him. 35 Jonadab said to the king, “Behold, the king’s sons are coming! It is as your servant said.” 36 It happened, as soon as he had finished speaking, that behold, the king’s sons came, and lifted up their voice, and wept. The king also and all his servants wept bitterly. 37 But Absalom fled, and went to Talmai the son of Ammihur, king of Geshur. David mourned for his son every day. 38 So Absalom fled, and went to Geshur, and was there three years.
Matthew Henry's Commentary on 2 Samuel 13:28-38
Commentary on 2 Samuel 13:21-29
(Read 2 Samuel 13:21-29)
Observe the aggravations of Absalom's sin: he would have Ammon slain, when least fit to go out of the world. He engaged his servants in the guilt. Those servants are ill-taught who obey wicked masters, against God's commands. Indulged children always prove crosses to godly parents, whose foolish love leads them to neglect their duty to God.
Commentary on 2 Samuel 13:30-39
(Read 2 Samuel 13:30-39)
Jonadab was as guilty of Ammon's death, as of his sin; such false friends do they prove, who counsel us to do wickedly. Instead of loathing Absalom as a murderer, David, after a time, longed to go forth to him. This was David's infirmity: God saw something in his heart that made a difference, else we should have thought that he, as much as Eli, honoured his sons more than God.