The curse of David proves that Joab was not justified as blood-revenger or Goel 2 Samuel 3:27 in taking away Abner’s life.
That leaneth on a staff - Rather, a crutch. The phrase denotes one lame or infirm. For similar instances of hereditary disease and poverty as a punishment of great sin, see 1 Samuel 2:31-33, 1Sa 2:36; 2 Kings 5:27; John 9:2.