20 In his time, Edom made themselves free from the rule of Judah, and took a king for themselves. 21 Then Joram went over to Zair, with all his war-carriages; ... made an attack by night on the Edomites, whose forces were all round him, ... the captains of the war-carriages; and the people went in flight to their tents. 22 So Edom made themselves free from the rule of Judah to this day. And at the same time, Libnah made itself free.
Matthew Henry's Commentary on 2 Kings 8:20-22
Commentary on 2 Kings 8:16-24
(Read 2 Kings 8:16-24)
A general idea is given of Jehoram's badness. His father, no doubt, had him taught the true knowledge of the Lord, but did ill to marry him to the daughter of Ahab; no good could come of union with an idolatrous family.