John Wesley on 2 Samuel 3:31

Joab - Him he especially obliged to it, to bring him to repentance for his sin, and to expose him to public shame. Followed - That is, attending upon his corps, and paying him that respect which was due to his quality. Though this was against the usage of kings, and might seem below David's dignity; yet it was now expedient to vindicate himself from all suspicion of concurrence in this action.