In the time of Jehoram, Edom rebelled against Judah and set up its own king.
References for 2 Kings 8:20
So Jehoram went to Zair with all his chariots. The Edomites surrounded him and his chariot commanders, but he rose up and broke through by night; his army, however, fled back home.
References for 2 Kings 8:21
To this day Edom has been in rebellion against Judah. Libnah revolted at the same time.
References for 2 Kings 8:22
As for the other events of Jehoram’s reign, and all he did, are they not written in the book of the annals of the kings of Judah?
Jehoram rested with his ancestors and was buried with them in the City of David. And Ahaziah his son succeeded him as king.
In the twelfth year of Joram son of Ahab king of Israel, Ahaziah son of Jehoram king of Judah began to reign.
References for 2 Kings 8:25
Ahaziah was twenty-two years old when he became king, and he reigned in Jerusalem one year. His mother’s name was Athaliah, a granddaughter of Omri king of Israel.
References for 2 Kings 8:26
He followed the ways of the house of Ahab and did evil in the eyes of the LORD, as the house of Ahab had done, for he was related by marriage to Ahab’s family.
References for 2 Kings 8:27
Ahaziah went with Joram son of Ahab to war against Hazael king of Aram at Ramoth Gilead. The Arameans wounded Joram;
References for 2 Kings 8:28
so King Joram returned to Jezreel to recover from the wounds the Arameans had inflicted on him at Ramoth in his battle with Hazael king of Aram. Then Ahaziah son of Jehoram king of Judah went down to Jezreel to see Joram son of Ahab, because he had been wounded.
References for 2 Kings 8:29