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. 19 Moreover, Josiah removed all the shrines of the high places that were in the towns of Samaria, which kings of Israel had made, provoking the Lord to anger; he did to them just as he had done at Bethel 20 He slaughtered on the altars all the priests of the high places who were there, and burned human bones on them. Then he returned to Jerusalem.
21 The king commanded all the people, "Keep the passover to the Lord your God as prescribed in this book of the covenant. 22 No such passover had been kept since the days of the judges who judged Israel, even during all the days of the kings of Israel and of the kings of Judah; 23 but in the eighteenth year of King Josiah this passover was kept to the Lord in Jerusalem.
24 Moreover Josiah put away the mediums, wizards, teraphim, idols, and all the abominations that were seen in the land of Judah and in Jerusalem, so that he established the words of the law that were written in the book that the priest Hilkiah had found in the house of the Lord.
Matthew Henry's Commentary on 2 Kings 23:15-24
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.