During Jehoram's reign, Edom rebelled against Judah's domination and appointed their own king.
So Jehoram crossed [into Edom] with his commanders and all his chariots. Then at night he set out to attack the Edomites who had surrounded him and the chariot commanders.
So Edom is still in rebellion against Judah's domination today. Libnah also rebelled at that time against his domination because he had abandoned the Lord God of his ancestors.
References for 2 Chronicles 21:10
Jehoram also built high places in the hills of Judah, and he caused the inhabitants of Jerusalem to prostitute themselves, and he led Judah astray.
References for 2 Chronicles 21:11
Then a letter came to Jehoram from Elijah the prophet, saying: This is what the Lord God of your ancestor David says: "Because you have not walked in the ways of your father Jehoshaphat or in the ways of Asa king of Judah
References for 2 Chronicles 21:12
but have walked in the way of the kings of Israel, have caused Judah and the inhabitants of Jerusalem to prostitute themselves like the house of Ahab prostituted itself, and also have killed your brothers, your father's family, who were better than you,
the Lord is now about to strike your people, your sons, your wives, and all your possessions with a horrible affliction.
You yourself [will be struck] with many illnesses, including a disease of the intestines, until your intestines come out day after day because of the disease."
References for 2 Chronicles 21:15