2 Kings 10:11
So Jehu slew all that remained of the house of Ahab in Jezreel, and all his great men, and his kinsfolks, and his priests, until he left him none remaining. So Jehu slew all that remained of the house of Ahab in Jezreel, and all his great men, and his kinsfolks, and his priests, until he left him none remaining.
In Jezreel Jehu slew all that remained of the house of Ahab, until he left him none remaining. Those put to death with them included his great men, his kinsfolk, and his priests. Their deaths were part of work against those who had chosen to continue in sin and to lead others into sin.
The execution was divinely appointed judgment on Ahab's dynasty for its sin and for the killing of the Lord's servants and prophets. Together with the removal of Baal and Ashtoreth worship, the killing was permitted by God in compassion for a morally weak Israel, so that by removing temptation some people would be given the chance to turn from heathenism and seek God. Israel's calamities were judgments tempered with mercy, and when their purpose was fulfilled, God turned events in favor of those who had learned to seek Him.
Jehu's zeal against Ahab's house warns that zeal can become self-driven and lead to harsh, unbefitting words. The verse therefore cautions to present truth with gentleness and love, rather than pouring out words that fail to revive or win souls.