2 Samuel 3
David’s governmental activities, including the payment of his troops and extending his influence throughout the territory. Since David had no administrative system for gathering income, he continued his earlier practice of conducting raids against Israel’s enemies to create the necessary revenues (cf. 1 Sam 27:8–11; 30:26), just as the rival king Ish-Bosheth did (cf. 2 Sam 4:2).
However, when Joab learned of the negotiations with Abner (v. 23), he was livid. Abner was Joab’s most hated enemy, especially because of his role in Asahel’s death (cf. 2:23). Joab did not believe this rival general could be trusted to provide sincere support for David, since Abner was a member of Saul’s family. Furthermore, Abner also was the single greatest threat to Joab’s own position of supreme military leadership; it is almost certain that David would give Abner key military responsibilities
24 Then Joab went to the king and said, “What have you done? Behold, Abner came to you. Why is it that you have sent him away, so that he is gone? 25 You know that Abner the son of Ner came to deceive you and to know your going out and your coming in, and to know all that you are doing.”