2 Chronicles 30:15-17

15And on the fourteenth day of the second month they slaughtered the Passover lamb. The priests and Levites were ashamed, and they consecrated themselves and brought burnt offerings to the house of the LORD.

16They stood at their prescribed posts, according to the Law of Moses the man of God. The priests splattered the blood, which they received from the hand of the Levites. 17Since there were many in the assembly who had not consecrated themselves, the Levites were in charge of slaughtering the Passover lambs for every unclean person to consecrate the lambs to the LORD.