2 Kings 10:25
And it came to pass, as soon as he had made an end of offering the burnt offering, that Jehu said to the guard and to the captains, Go in, and slay them; let none come forth. And they smote them with the edge of the sword; and the guard and the captains cast them out, and went to the city of the house of Baal.
The slaying commanded the moment the burnt offering was finished was carried out by the guard and the captains against the priests and worshipers of Baal gathered inside, wiping out the worship of Baal and Ashtoreth with the destruction and forsaking of their altars. That killing was part of stern measures of reform under Jehu that included the slaying of all the house of Ahab. It came after judgment upon judgment had fallen on apostate Israel during the reign of Hazael of Syria, who had been anointed to be its scourge. It belonged to the reformation begun by Elijah and carried forward by Elisha.
The destruction was a merciful providence in which God removed a source of temptation, so that some in Israel might forsake heathenism, inquire after God, and turn to serve Him with all the heart. Calamities and judgments were thus tempered with mercy to lead people to seek God and to fulfill His purpose in those who chose Him. Yet Jehu's forceful conduct also warns that zeal can give way to self and break out in torrents of harsh, unsuitable words instead of speech that refreshes and wins souls.