Background:
Jehoram, son of Jehoshaphat, was the king of Judah who reigned in the 9th century BC. His reign is noted for its departure from the ways of his father, Jehoshaphat, who had been a righteous king. Jehoram's marriage to Athaliah, the daughter of Ahab and Jezebel, further influenced his turn towards idolatry and evil practices, aligning Judah more closely with the northern kingdom of Israel, which was steeped in Baal worship.

The Prophecy:
The prophecy against Jehoram is a significant event recorded in 2 Chronicles 21:12-15. It is unique in that it is delivered through a letter from the prophet Elijah, who had primarily been active in the northern kingdom of Israel. This letter serves as a divine indictment against Jehoram for his apostasy and the resulting consequences for his actions.

Content of the Prophecy:
The letter from Elijah begins with a direct rebuke of Jehoram's departure from the righteous path of his forefathers. Elijah writes, "This is what the LORD, the God of your father David, says: 'You have not walked in the ways of your father Jehoshaphat or of Asa king of Judah, but you have walked in the ways of the kings of Israel, and you have led Judah and the people of Jerusalem to prostitute themselves, just as the house of Ahab prostituted themselves. You have also murdered your own brothers, members of your own family, men who were better than you.'" (2 Chronicles 21:12-13).

The prophecy continues with a pronouncement of judgment: "So now the LORD is about to strike your people, your sons, your wives, and all your possessions with a heavy blow. You yourself will be struck with a severe illness, a disease of your bowels, until your bowels come out day by day because of the disease." (2 Chronicles 21:14-15).

Fulfillment:
The prophecy's fulfillment is recorded in the subsequent verses of 2 Chronicles 21. The LORD stirred up the Philistines and the Arabs against Jehoram, and they carried away all the possessions found in the king's house, including his sons and wives, leaving only his youngest son, Jehoahaz. Furthermore, Jehoram was afflicted with a painful and incurable disease of the bowels, which eventually led to his death after two years of suffering, as foretold by Elijah.

Theological Significance:
Elijah's prophecy against Jehoram underscores the seriousness with which God views idolatry and the abandonment of His covenant. It serves as a stark reminder of the consequences of leading a nation away from the worship of Yahweh. The prophecy also highlights God's faithfulness to His covenant with David, as the judgment is framed within the context of Jehoram's failure to walk in the ways of his righteous ancestors. Despite Jehoram's unfaithfulness, God's overarching plan for the Davidic line remains intact, pointing ultimately to the coming of the Messiah.

Historical Context:
The historical context of Elijah's prophecy is set during a turbulent period in the history of the divided kingdoms of Israel and Judah. The influence of Ahab and Jezebel's idolatry had permeated both kingdoms, leading to widespread apostasy. Elijah's ministry, though primarily focused on Israel, extends to Judah through this prophecy, demonstrating the interconnectedness of the two kingdoms and the pervasive nature of the spiritual decline during this era.