What does the Bible say about King Jehu?

Jehu's part was that of a reformer, he was one of the three persons that God instructed Elijah to anoint to carry out his purpose in 1Kings 19:15-17, "Anoint Hazael king over Aram. Also, anoint Jehu son of Nimshi king over Israel, and anoint Elisha son of Shaphat from Abel Meholah to succeed you as prophet. Jehu will put to death any who escape the sword of Hazael, and Elisha will put to death any who escape the sword of Jehu”

He ruled after King Ahab and Jezebel and his role were to by God's strength wipe out the house of Ahab and to stop the worship of Baal in Israel. Jehu was responsible for killing most persons linked with the house of Ahab, including Jezebel(Ahab's wife), Joram (King of Northern Israel), Ahaziah (King of Judah). Jehu ruled for twenty-eight years.