3:22 Now David’s soldiers and Joab were coming back from a raid, bringing a great deal of plunder with them. Abner was no longer with David in Hebron, for David had sent him away and he had left in peace. 3:23 When Joab and all the army that was with him arrived, Joab was told: “Abner the son of Ner came to the king; he sent him away, and he left in peace!”
3:24 So Joab went to the king and said, “What have you done? Abner has come to you! Why would you send him away? Now he’s gone on his way! 3:25 You know Abner the son of Ner! Surely he came here to spy on you and to determine when you leave and when you return and to discover everything that you are doing!”
3:26 Then Joab left David and sent messengers after Abner. They brought him back from the well of Sirah. (But David was not aware of it.) 3:27 When Abner returned to Hebron, Joab took him aside at the gate as if to speak privately with him. Joab then stabbed him in the abdomen and killed him, avenging the shed blood of his brother Asahel.