David said to Joab; him he especially obliged to it; partly to bring him to repentance for his sin; partly to expose him to public shame, and to the contempt and hatred of all the people, with whom he had too great an interest, which hereby David designed to diminish. Mourn before Abner, i.e. attending upon his corpse, and paying him that respect and honour which was due to his quality. King David himself followed the bier; which was against the usage of kings, and might seem below David's dignity; but it was now expedient, to vindicate himself from all suspicion and contrivance or concurrence in this action.
Related Commentaries of 2 Samuel 3:31
2 Samuel 3:31
31 And David said to Joab, and to all the people that were with him, Rend your clothes, and gird you with sackcloth, and mourn before Abner. And king David himself followed the bier.h