2 Samuel 3:30

26 As soon as Joab had left David, he sent messengers after Abner, who brought him back from the well of Sirah; but David was unaware of it.

27 When Abner returned to Hebron, Joab pulled him aside into the gateway, as if to speak to him privately, and there Joab stabbed him in the stomach. So Abner died on account of the blood of Joab’s brother Asahel.

28 Afterward, David heard about this and said, “I and my kingdom are forever guiltless before the LORD concerning the blood of Abner son of Ner.

29 May it whirl over the heads of Joab and the entire house of his father, and may the house of Joab never be without one having a discharge or skin disease, or one who leans on a staff or falls by the sword or lacks food.”

30 (Joab and his brother Abishai murdered Abner because he had killed their brother Asahel in the battle at Gibeon.)

31 Then David ordered Joab and all the people with him, “Tear your clothes, put on sackcloth, and mourn before Abner.” And King David himself walked behind the funeral bier.

32 When they buried Abner in Hebron, the king wept aloud at Abner’s tomb, and all the people wept.

33 And the king sang this lament for Abner: “Should Abner die the death of a fool?

34 Your hands were not bound, your feet were not fettered. As a man falls before the wicked, so also you fell.” And all the people wept over him even more.

Read all of 2 Samuel 3