1 Kings 16:21 - Joseph Benson’s Commentary on the Old and New Testaments

Then were the people of Israel divided into two parts Which contended, and went to war with each other about the person that should reign over them. For when it is said, (1 Kings 16:16,) all Israel made Omri king, the meaning is, only the whole army, and such as attended them. Half of the people followed Tibni These, it is probable, did not like to have a king imposed upon them by the soldiery: and Tibni had as good a title as the other, being also a valiant man, and the person, perhaps, who succeeded Zimri, in his command, as captain of half the king's chariots. The contest between him and Omri lasted some years, and, it is likely, cost much blood on both sides. But neither this civil war, nor any other of God's dreadful judgments, could bring them to repentance, which is an evidence of their prodigious impiety and incorrigibleness, and how ripe they were for ruin.