Matthew Poole and continuators on 1 Kings 16:23

23 ¶ In the thirty and one year of Asa king of Judah, began Omri to reign over Israel twelve years : six years reigned he in Tirzah.

i. e. And he Reigned Twelve Years, not from this 31 year of Asa, for he died in his 38 year. ver. 29. but from the beginning of his Reign, which was in Asa's 27 year, ver. 15, 16 So he Reigned four years in a State of War with Tibni, and Eight years peaceably.