2 Samuel 2:10
Ish-bosheth Saul’s son was forty years old when he began to reign over Israel, and reigned two years. But the house of Judah followed David. Ish-bosheth Saul’s son was forty years old when he began to reign over Israel, and reigned two years. But the house of Judah followed David.
After Judah acknowledged David as king, Abner had Ishbosheth, Saul's son, proclaimed king over Israel and set on a rival throne, leaving the kingdom divided with the house of Judah following David. His rule began with the tribes east of the Jordan and afterward extended over all Israel except Judah, while the house of Judah remained loyal to David. He reigned two years from Mahanaim, which was chosen as a secure royal residence. Since David's authority as king came from God, this rival kingship was rebellion against the king God had chosen. War continued between the house of Saul and the house of David, and during this conflict David's power grew while Saul's house weakened.