Jehu Over Israel
Jehu begins his bloody deed of wiping out the house of Ahab, pursuant to Elisha's prophecy. Seventy of Ahab's sons lived in Samaria (2 Kings 10:1 2 Kings 10:1And Ahab had seventy sons in Samaria. And Jehu wrote letters, and sent to Samaria, to the rulers of Jezreel, to the elders, and to them that brought up Ahab's children, saying,
American King James Version×). When Jehu threatens the city, the elders slaughter the sons and deliver their heads in baskets to Jehu in Jezreel (verses 2-8). Jehu then proceeds to kill everyone remaining from the house of Ahab (verse 11, 17). He also kills the brothers of the late King Ahaziah of Judah (2 Kings 10:12-14 2 Kings 10:12-14  And he arose and departed, and came to Samaria. And as he was at the shearing house in the way,  Jehu met with the brothers of Ahaziah king of Judah, and said, Who are you? And they answered, We are the brothers of Ahaziah; and we go down to salute the children of the king and the children of the queen.  And he said, Take them alive. And they took them alive, and slew them at the pit of the shearing house, even two and forty men; neither left he any of them.
American King James Version×), as well as all the priests of Baal (verses 18-28). As we saw earlier, he was eradicating the line of Ahab even across national boundaries.
Jehu, however, was by no means a righteous ruler. Although he seemed to understand that he was an instrument in God's hands, carrying out God's vengeance on the house of Ahab and "destroying Baal from Israel" (verse 28), he himself did not obey God in other matters (verse 29). While God rewarded him for what he did do in accordance with His will (verse 30), this does not mean that Jehu lived a life pleasing to God.
The Nelson Study Bible comments: "Jehu's merciless purge of the official Baal priesthood was a major step in eradicating evil from the northern kingdom. However, the purge only brought Israel back to the syncretism established by Jeroboam I and his successors. God rewarded Jehu with a reign of twenty-eight years, the longest of any northern king so far, and allowed his sons to rule Israel for four more generations, the longest dynasty in Israel's history. Jehu had an opportunity to be one of the greatest kings, but he did not follow God's law completely. He did not stop the worship of the golden calves left at Dan and Bethel. While not as overt as during the time of Ahab, the slide to Baal worship in Israel continued even after Jehu's purge of the worshipers of Baal. Tragically, Jehu did not take the opportunity to lead the Israelites back to complete obedience of God's law" ("INDepth: A Missed Opportunity: Jehu," sidebar on 2 Kings 10).
Rather, we read, "Jehu took no heed to walk in the law of the Lord God of Israel with all his heart; for he did not depart from the sins of Jeroboam, who had made Israel sin" (verse 31). This example shows that not everyone used by God for a specific purpose must also be a truly repentant believer.
This story also shows the tragic continuing negative heritage of Jeroboam I, whose disobedience and false religion set a pattern of habit and tradition for the nation and its kings from which it was very difficult to break free. Repeatedly throughout the history of Israel's kings, we read the phrase, "the sins of Jeroboam, who made Israel to sin." Seeing his great potential, God had offered him a dynasty like that of David (1 Kings 11:38 1 Kings 11:38And it shall be, if you will listen to all that I command you, and will walk in my ways, and do that is right in my sight, to keep my statutes and my commandments, as David my servant did; that I will be with you, and build you a sure house, as I built for David, and will give Israel to you.
American King James Version×). But, like Lucifer, Jeroboam chose to use his wonderful talent for evil instead of for good.
Athaliah Over Judah
After Ahaziah, king of Judah, had been killed by Jehu, Ahaziah's mother Athaliah tried to kill all the royal heirs so that she could reign over the land. Here we see another woman of power corrupting herself with the lust for greater influence. However, Ahaziah's sister, Jehosheba, saved Ahaziah's son Joash (or Jehoash) from death and hid him for six years (2 Kings 11:1-3 2 Kings 11:1-3  And when Athaliah the mother of Ahaziah saw that her son was dead, she arose and destroyed all the seed royal.
 But Jehosheba, the daughter of king Joram, sister of Ahaziah, took Joash the son of Ahaziah, and stole him from among the king's sons which were slain; and they hid him, even him and his nurse, in the bedchamber from Athaliah, so that he was not slain.
 And he was with her hid in the house of the LORD six years. And Athaliah did reign over the land.
American King James Version×; 2 Chronicles 22:10-12 2 Chronicles 22:10-12  But when Athaliah the mother of Ahaziah saw that her son was dead, she arose and destroyed all the seed royal of the house of Judah.  But Jehoshabeath, the daughter of the king, took Joash the son of Ahaziah, and stole him from among the king's sons that were slain, and put him and his nurse in a bedchamber. So Jehoshabeath, the daughter of king Jehoram, the wife of Jehoiada the priest, (for she was the sister of Ahaziah,) hid him from Athaliah, so that she slew him not.  And he was with them hid in the house of God six years: and Athaliah reigned over the land.
American King James Version×). Jehosheba, also called Jehoshabeath, was the wife of Jehoiada the priest. Her courageous character is a refreshing contrast to the evil queen.
Ironically, Athaliah's actions further purged the Davidic family of Ahab's corrupt lineage. But Joash would survive to reign, as we will see. Yet Joash was himself of Ahab's lineage, being the son of Athaliah's son, King Ahaziah. So why did God allow him to survive? To understand, we must consider the problem with Ahab's lineage in Judah. Remember that after Jehoshaphat's son Jehoram married Ahab's daughter Athaliah, this evil and idolatrous woman became mother and grandmother to many Davidic princes and princesses. Thus the line of Ahab became widely diffused throughout the Jewish royal family. Being queen, mother and grandmother to these other royals enabled her to have a great and corrupting influence on them. This wide diffusion with its accompanying corruption was the real problem. That is why these people needed to go. And through the purges carried out by Jehu and Athaliah herself, all of these corrupt individuals were wiped out. No longer was Ahab's idolatrous lineage widely diffused throughout the family of David. Only one line of descent from Ahab would be allowed to continue--that of Joash, who as a baby was removed from any corrupting influence of other relatives of Ahab's lineage, particularly Athaliah.