Verses 21 through 28a speak of the reign of Omri over Israel.
The people of Israel were divided into two. Half went after Tibni, making him king, and half went after Omri (v. 21).
The people who followed Omri prevailed over the people who followed Tibni, and Omri began to reign after the death of Tibni (v. 22).
In the thirty-first year of Asa king of Judah, Omri reigned over Israel for twelve years, reigning six years in Tirzah (v. 23).
Omri purchased the hill of Samaria and built a city upon the hill and called the name of the city that he built Samaria (v. 24).
Omri did evil in the sight of Jehovah more than all who were before him and went in all the way of Jeroboam and in his sin by which he caused Israel to sin, provoking Jehovah to anger with their idols (vv. 25-27).
Omri died and was buried in Samaria (v. 28a).