2 Chronicles 30:13-17

And many people came together in Jerusalem to keep the Feast of Unleavened Bread in the second month, a very great assembly. They set to work and removed the altars that were in Jerusalem, and all the altars for burning incense they took away and threw into the brook Kidron. And they slaughtered the Passover lamb on the fourteenth day of the second month. And the priests and the Levites were ashamed, so that they consecrated themselves and brought burnt offerings into the house of the LORD. They took their accustomed posts according to the Law of Moses the man of God. The priests threw the blood that they received from the hand of the Levites. For there were many in the assembly who had not consecrated themselves. Therefore the Levites had to slaughter the Passover lamb for everyone who was not clean, to consecrate it to the LORD.