2 Kings 23:20-24

He slaughtered on the altars all the priests of those high places, and he burned human bones on the altars. Then he returned to Jerusalem.

The king commanded all the people, “Observe the Passover of the Lord your God as written in the book of the covenant.”

No such Passover had ever been observed from the time of the judges who judged Israel through the entire time of the kings of Israel and Judah.

But in the eighteenth year of King Josiah, the Lord’s Passover was observed in Jerusalem.

In addition, Josiah eradicated the mediums, the spiritists, household idols, images, and all the abhorrent things that were seen in the land of Judah and in Jerusalem. He did this in order to carry out the words of the law that were written in the book that the priest Hilkiah found in the Lord’s temple.