In 2 Samuel 3:12–21, Abner, Saul and Ish-Bosheth’s general, proposed to David that they make an agreement (a covenant) and that he would help David secure Israel. David demanded that Abner restore, as a sign of his good faith, his long-separated wife Michal to him (2 Samuel 3:13–14; 1 Sam. 18:20–27; 25:44). After this was accomplished (2 Samuel 3:15–16), Abner met with Israel’s elders, especially those from Benjamin, Saul’s own tribe, and persuaded them that the rule of David over them was in their best interest. This, of course, elevated Abner considerably in David’s estimation, which greatly displeased David’s loyal men.
In 2 Samuel 3:22–39. Joab was enraged when he found out that David had entertained Abner at a feast (2 Samuel 3:20). First, Joab, made overtures of friendship to Abner (2 Samuel 3:22). Then he chided the king, saying that Abner’s purpose was to spy on David (2 Samuel 3:24–25). Joab then took measures to have Abner return to Hebron from the well of Sirah (site unknown). Pretending to whisper something of importance to Abner … Joab drew him aside and viciously assassinated him (stabbed him in the stomach, v. 27; cf. 4:5–6). This was in revenge for Abner’s murder of Joab’s brother Asahel (3:27, 30; 2:23).
When David discovered what had happened, he did not rejoice but rather uttered a curse on Joab and his progeny (3:29). Joab’s murder of Abner took place in Hebron, a city of refuge (Josh. 21:13), where such revenge was not permitted (Num. 35:22–25). David then proclaimed a public mourning (2 Sam. 3:31), buried Abner in honor at Hebron (v. 32), and composed a lamentation (vv. 33–34) in which he spoke of the shameful way in which Abner had died. David’s compassion and forgiving spirit are evident here, qualities which separated him from ordinary men.
As a sign of his sincerity, David took a vow to fast. He also said that he was weak compared with Abner. Though he knew that the sons of Zeruiah (Joab and his brothers) must be punished, he did not know how to undertake it (vv. 35–39). Zeruiah was David’s half sister (1 Chron. 2:16; cf. 2 Sam. 2:18 and see the chart “David’s Family”).