Background and Historical Context:
Jehu, son of Jehoshaphat and grandson of Nimshi, emerges as a pivotal figure in the history of Israel during the tumultuous period of the divided monarchy. His rise to power is chronicled in the books of 1 and 2 Kings, where he is depicted as an instrument of divine judgment against the house of Ahab. Jehu's reign marks a significant turning point in the northern kingdom's history, characterized by a zealous purge of Baal worship and the eradication of Ahab's lineage.

Anointing and Divine Commission:
The anointing of Jehu as king is a direct fulfillment of God's command to Elijah, as recorded in 1 Kings 19:16, where the prophet is instructed to anoint Jehu as king over Israel. This task is later carried out by Elisha, Elijah's successor, who sends one of the sons of the prophets to anoint Jehu. The account in 2 Kings 9:1-13 details this event, where the young prophet finds Jehu among his fellow officers and anoints him with oil, declaring, "This is what the LORD, the God of Israel, says: ‘I anoint you king over the LORD’s people Israel.’" (2 Kings 9:6).

Jehu's Zeal and Judgment on the House of Ahab:
Jehu's anointing sets in motion a series of events that fulfill God's judgment against the house of Ahab, as prophesied by Elijah. Jehu's first act as king is to confront and kill Joram, the reigning king of Israel and son of Ahab, as well as Ahaziah, king of Judah, who was allied with Joram. This decisive action is recorded in 2 Kings 9:14-29.

Jehu's zeal for the LORD is further demonstrated in his confrontation with Jezebel, Ahab's notorious wife, who is thrown from a window and trampled underfoot, fulfilling Elijah's prophecy that dogs would devour her flesh (2 Kings 9:30-37). Jehu's campaign of judgment continues with the eradication of Ahab's seventy sons in Samaria, as well as the execution of all who remained of Ahab's house, his chief men, close friends, and priests, leaving no survivor (2 Kings 10:1-11).

Religious Reforms and the End of Baal Worship:
Jehu's reign is marked by significant religious reforms, most notably the destruction of Baal worship in Israel. In a cunning plan, Jehu gathers all the prophets and worshipers of Baal under the pretense of a grand sacrifice, only to have them slaughtered, thus purging Baal worship from the land (2 Kings 10:18-28). Despite his zeal, Jehu fails to turn away from the sins of Jeroboam, the first king of the northern kingdom, who led Israel into idolatry with the golden calves at Bethel and Dan (2 Kings 10:29-31).

Legacy and Evaluation:
Jehu's reign, lasting twenty-eight years, is a complex period of both commendation and criticism. While he is praised for his obedience in executing God's judgment on Ahab's house and eradicating Baal worship, his failure to fully turn Israel back to the LORD and his continuation of Jeroboam's idolatry mar his legacy. The LORD acknowledges Jehu's actions by promising that his descendants would sit on the throne of Israel to the fourth generation (2 Kings 10:30). However, the LORD also begins to reduce the size of Israel during his reign, as Hazael of Aram defeats them in several battles (2 Kings 10:32-33).

Jehu's account serves as a reminder of the importance of wholehearted devotion to God and the consequences of incomplete obedience. His life and reign are a testament to God's sovereignty and the fulfillment of His prophetic word, as well as a cautionary tale of the dangers of failing to fully adhere to God's commands.