David battles against Abner at Gibeon
There was civil war between David and Ish-bosheth. Joab and David’s men defeated Abner’s army at Gibeon. Abner killed Joab’s brother Asahel in the battle.
Key passages
2 Sa 2:12–29

Abner the son of Ner and the servants of Ish-Bosheth the son of Saul went out from Mahanaim to Gibeon. Then Joab the son of Zeruiah and the servants of David went out, and they met at the pool of Gibeon. The one group sat on one side of the pool, and the other …

See also
2 Sa 3:30;