Albert Barnes Commentary 2 Kings 8:22

"So Edom revolted from under the hand of Judah unto this day. Then did Libnah revolt at the same time." — 2 Kings 8:22 (ASV)

Libnah revolted. Since Libnah was located in the southwest of Palestine (Joshua 15:42), its revolt could not have had any direct connection with that of Edom.

Before its conquest by Joshua, Libnah had been the capital of a small Canaanite state under its own king (Joshua 10:30; Joshua 12:15), and it may have always retained a considerable Canaanite population. Alternatively, its loss may have been connected with the attacks made by the Philistines on Jehoram’s territories (2 Chronicles 21:16–17).