21:1-11 Jehoram hated his brethren, and slew them, for the same reason that Cain hated Abel, and slew him, because their piety condemned his impiety. In the mystery of Providence such men sometimes prosper for a time; but the Lord has righteous purposes in permitting such events, part of which may now be made out, and the rest will be seen hereafter.

2Ch 21:8-17. Edom and Libnah Revolt.

8-10. the Edomites revolted—That nation had been made dependent by David, and down to the time of Jehoshaphat was governed by a tributary ruler (1Ki 22:47; 2Ki 3:9). But that king having been slain in an insurrection at home, his successor thought to ingratiate himself with his new subjects by raising the flag of independence [Josephus]. The attempt was defeated in the first instance by Jehoram, who possessed all the military establishments of his father; but being renewed unexpectedly, the Edomites succeeded in completely emancipating their country from the yoke of Judah (Ge 27:40). Libnah, which lay on the southern frontier and towards Edom, followed the example of that country.