15 Now when he departed from there, he met Jehonadab the son of Rechab, coming to meet him; and he greeted him and said to him, "Is your heart right, as my heart is toward your heart?" And Jehonadab answered, "It is." Jehu said, "If it is, give me your hand." So he gave him his hand, and he took him up to him into the chariot. 16 Then he said, "Come with me, and see my zeal for the Lord." So they had him ride in his chariot. 17 And when he came to Samaria, he killed all who remained to Ahab in Samaria, till he had destroyed them, according to the word of the Lord which He spoke to Elijah.
18 Then Jehu gathered all the people together, and said to them, "Ahab served Baal a little, Jehu will serve him much. 19 Now therefore, call to me all the prophets of Baal, all his servants, and all his priests. Let no one be missing, for I have a great sacrifice for Baal. Whoever is missing shall not live." But Jehu acted deceptively, with the intent of destroying the worshipers of Baal. 20 And Jehu said, "Proclaim a solemn assembly for Baal." So they proclaimed it. 21 Then Jehu sent throughout all Israel; and all the worshipers of Baal came, so that there was not a man left who did not come. So they came into the temple of Baal, and the temple of Baal was full from one end to the other. 22 And he said to the one in charge of the wardrobe, "Bring out vestments for all the worshipers of Baal." So he brought out vestments for them. 23 Then Jehu and Jehonadab the son of Rechab went into the temple of Baal, and said to the worshipers of Baal, "Search and see that no servants of the Lord are here with you, but only the worshipers of Baal."
Matthew Henry's Commentary on 2 Kings 10:15-23
Commentary on 2 Kings 10:15-28
(Read 2 Kings 10:15-28)
Is thine heart right? This is a question we should often put to ourselves. I make a fair profession, have gained a reputation among men, but, is my heart right? Am I sincere with God? Jehonadab owned Jehu in the work, both of revenge and of reformation. An upright heart approves itself to God, and seeks no more than his acceptance; but if we aim at the applause of men, we are upon a false foundation. Whether Jehu looked any further we cannot judge. The law of God was express, that idolaters were to be put to death. Thus idolatry was abolished for the present out of Israel. May we desire that it be rooted out of our hearts.