1 Kings 16:23 - Clarke's commentary and critical notes on the Bible

In the thirty and first year of Asa king of Judah began Omri to reign over Israel, twelve years: six years reigned he in Tirzah. In the thirty and first year of Asa - There must be a mistake here in the number thirty-one; for, in 1 Kings 16:10 and 1 Kings 16:15, it is said that Zimri slew his master, and began to reign in the twenty-seventh year of Asa; and as Zimri reigned only seven days, and Omri immediately succeeded him, this could not be in the thirty-first, but in the twenty-seventh year of Asa, as related above. Rab. Sol. Jarchi reconciles the two places thus: "The division of the kingdom between Tibni and Omri began in the twenty-seventh year of Asa; this division lasted five years, during which Omri had but a share of the kingdom. Tibni dying, Omri came into the possession of the whole kingdom, which he held seven years; this was in the thirty-first year of Asa. Seven years he reigned alone; five years he reigned over part of Israel; twelve years in the whole. The two dates, the twenty-seventh and thirty-first of Asa, answering, the first to the beginning of the division, the second to the sole reign of Omri." Jarchi quotes Sedar Olam for this solution.