15 Moreover, the altar at Bethel, the high place erected by Jeroboam son of Nebat, who caused Israel to sin-he pulled down that altar along with the high place. He burned the high place, crushing it to dust; he also burned the sacred pole. 16 As Josiah turned, he saw the tombs there on the mount; and he sent and took the bones out of the tombs, and burned them on the altar, and defiled it, according to the word of the Lord that the man of God proclaimed, when Jeroboam stood by the altar at the festival; he turned and looked up at the tomb of the man of God who had predicted these things. 17 Then he said, "What is that monument that I see?" The people of the city told him, "It is the tomb of the man of God who came from Judah and predicted these things that you have done against the altar at Bethel." 18 He said, "Let him rest; let no one move his bones." So they let his bones alone, with the bones of the prophet who came out of 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.