Joab left David and sent messengers to Abner at the well of Sirah. The messengers brought Abner back, but David did not know this.
You know Abner son of Ner. He came to trick you. He came to learn all about the things you are doing.”
When Abner arrived at Hebron, Joab took him to one side in the middle of the gateway to talk with him in private. And then Joab stabbed Abner in the stomach, and Abner died. Abner had killed Joab’s brother Asahel. So now Joab killed Abner.