II Chronicles 30:1-3, 13-20

And Hezekiah sent to all Israel and Judah, and also wrote letters to Ephraim and Manasseh, that they should come to the house of the LORD at Jerusalem, to keep the Passover to the LORD God of Israel. For the king and his leaders and all the assembly in Jerusalem had agreed to keep the Passover in the second month. For they could not keep it at the regular time, because a sufficient number of priests had not consecrated themselves, nor had the people gathered together at Jerusalem.

Now many people, a very great assembly, gathered at Jerusalem to keep the Feast of Unleavened Bread in the second month. They arose and took away the altars that were in Jerusalem, and they took away all the incense altars and cast them into the Brook Kidron. Then they slaughtered the Passover lambs on the fourteenth day of the second month. The priests and the Levites were ashamed, and sanctified themselves, and brought the burnt offerings to the house of the LORD. They stood in their place according to their custom, according to the Law of Moses the man of God; the priests sprinkled the blood received from the hand of the Levites. For there were many in the assembly who had not sanctified themselves; therefore the Levites had charge of the slaughter of the Passover lambs for everyone who was not clean, to sanctify them to the LORD. For a multitude of the people, many from Ephraim, Manasseh, Issachar, and Zebulun, had not cleansed themselves, yet they ate the Passover contrary to what was written. But Hezekiah prayed for them, saying, “May the good LORD provide atonement for everyone who prepares his heart to seek God, the LORD God of his fathers, though he is not cleansed according to the purification of the sanctuary.” And the LORD listened to Hezekiah and healed the people.