2 Samuel 2:8-17

Now [Saul’s cousin] Abner the son of Ner, commander of Saul’s army, had taken Ish-bosheth the son of Saul and brought him over to Mahanaim. He made him king over Gilead, over the Ashurites, over Jezreel, over Ephraim, over Benjamin, even over all Israel [except Judah]. Ish-bosheth, Saul’s son, was forty years old when he became king over Israel, and he reigned for two years. But the house of Judah followed David. And the time that David was king in Hebron over the house of Judah was seven years and six months. Now Abner the son of Ner and the servants of Ish-bosheth the son of Saul went out from Mahanaim to Gibeon. Joab [David’s nephew] the son of Zeruiah and the servants of David also went out and met them by the pool of Gibeon. They sat down, with one group on one side of the pool and the other group on the other side of the pool. Then Abner said to Joab, “Let the young men now stand and have a contest before us.” And Joab said, “Let them stand.” So they stood up and went over by number, twelve for Benjamin and Ish-bosheth the son of Saul, and twelve of the servants of David. Each one of them seized his opponent by the head and thrust his sword into his opponents side; so they fell down together. Therefore that place was called Helkath-hazzurim [that is, the Field of Sides], which is in Gibeon. There was a very fierce battle that day, and Abner and the men of Israel were beaten before the servants of David.