Josiah observed a Passover festival for the Lord in Jerusalem. ¹  They slaughtered the Passover lambs on the fourteenth day of the first month.

Hezekiah sent messages throughout Israel and Judah; he even wrote letters to Ephraim and Manasseh, summoning them to come to the Lord’s temple in Jerusalem ¹  and observe a Passover celebration for the Lord God of Israel.

So they sent an edict ¹  throughout Israel from Beer Sheba to Dan, summoning the people ²  to come and observe a Passover for the Lord God of Israel in Jerusalem, for they had not observed it on a nationwide scale as prescribed in the law. ³ 

A Passover like this had not been observed in Israel since the days of Samuel the prophet. None of the kings of Israel had observed a Passover like the one celebrated by Josiah, the priests, the Levites, all the people of Judah and Israel who were there, and the residents of Jerusalem.