2 Chronicles 30:16-17

16They stood at their accustomed stations, in accordance with the Law of Moses, the man of God. The priests sprinkled the blood [which they received] from the hand of the Levites [on the altar].

17For there were many in the assembly who had not consecrated themselves [that is, become ceremonially clean and free from all sin]; so the Levites had to slaughter the Passover lambs for everyone who was not clean, in order to make them holy for the Lord.