2 Kings 10:29-31 However Jehu did not turn away from the sins of Jeroboam the son of Nebat, who had made Israel sin, that is, from the golden calves that were at Bethel and Dan. And YHWH said to Jehu, “Because you have done well in doing what is right in My sight, and have done to the house of Ahab all that was in My heart, your sons shall sit on the throne of Israel to the fourth generation.” But Jehu took no heed to walk in the law of YHWH Elohim of Israel with all his heart; for he did not depart from the sins of Jeroboam, who had made Israel sin.

As explained in the point above on Jealous/Zealous, Jehu was prophesied and anointed by YHWH Himself to clean out the evil in Israel. Jehu was the 10th king of the northern kingdom of Israel and he was famous for his ruthless extermination of the house of Ahab. He reigned for 28 years, and even though he still tolerated the worship of the golden calves and was judged for it, his dynasty was secured on the throne for four generations (Jehoahaz, Jehoash, Jeroboam II, and Zachariah).

Jehu’s name in Hebrew is YEU H3058 – yêû’, actually put together by two words. “Yah (YHWH) is He“. If this is your first time reading the old testament, or you might have heard others say about the old testament, it is bloody, violent, wars and betrayals. It is a stark wake-up call to read about the bloody and violent killings, especially if one is used to the Bible of ancient wisdom and uplifting Psalms. But how quickly one can forget, and become complacent to the sins of Sodom, the sexual immorality. In just the previous chapters we read about the mothers who ate their own children, and the king who offered his son so he could have a war victory.

So yes Jehu was cunning, zealous and bloodthirsty by reputation, but YHWH used him to reform Israel and eradicate the baal worship.