Zimri"s seven-day reign in885 B.C. was the shortest in the history of the Northern Kingdom. [source][source][source]
Omri was commander-in-chief of Israel"s army. He outranked Zimri. When word of Zimri"s assassination of Elah reached the soldiers at Gibbethon (cf. 1 Kings 15:27), they immediately sided with their general and marched back to the capital to claim the throne for Omri. Zimri realized he could not oppose Omri successfully and chose suicide over execution. He also destroyed the palace in the process. It was because of his sins in following Jeroboam"s ways that God permitted Zimri to fail in his coup and to die ( 1 Kings 16:20). [source][source][source]
"Out of the chaos portrayed in this section will come Omri, a man who will stabilize the Northern Kingdom, establish a new capital, and begin a new dynasty. His family will rule through2Kings10. They will therefore occupy more of the story than any other northern dynasty. Omrides will also serve as active opponents of the prophets and as patrons of idolatry, especially of Baal worship." [1][source]