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.
Matthew Henry's Commentary on 2 Samuel 13:32
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.