15 The king also tore down the altar at Bethel-the pagan shrine that Jeroboam son of Nebat had made when he caused Israel to sin. He burned down the shrine and ground it to dust, and he burned the Asherah pole. 16 Then Josiah turned around and noticed several tombs in the side of the hill. He ordered that the bones be brought out, and he burned them on the altar at Bethel to desecrate it. (This happened just as the Lord had promised through the man of God when Jeroboam stood beside the altar at the festival.) Then Josiah turned and looked up at the tomb of the man of God who had predicted these things. 17 "What is that monument over there?" Josiah asked. And the people of the town told him, "It is the tomb of the man of God who came from Judah and predicted the very things that you have just done to the altar at Bethel!" 18 Josiah replied, "Leave it alone. Don't disturb his bones." So they did not burn his bones or those of the old prophet from Samaria.
Matthew Henry's Commentary on 2 Kings 23:15-18
Commentary on 2 Kings 23:15-24
(Read 2 Kings 23:15-24)
Josiah's zeal extended to the cities of Israel within his reach. He carefully preserved the sepulchre of that man of God, who came from Judah to foretell the throwing down of Jeroboam's altar. When they had cleared the country of the old leaven of idolatry, then they applied themselves to the keeping of the feast. There was not holden such a passover in any of the foregoing reigns. The revival of a long-neglected ordinance, filled them with holy joy; and God recompensed their zeal in destroying idolatry with uncommon tokens of his presence and favour. We have reason to think that during the remainder of Josiah's reign, religion flourished.