2 Chronicles 30:15-17

15Then they slaughtered the Passover lamb on the fourteenth day of the second month. The kohanim and the Levites were ashamed and consecrated themselves and brought burnt offerings into the House of Adonai.

16They stood at their post as prescribed in the Torah of Moses, the man of God. The kohanim sprinkled the blood that they received from the hand of the Levites.

17For there were many in the congregation that had not concecrated themselves, therefore the Levites were in charge of slaughtering the Passover lambs for everyone that was not ceremonially clean in order to concecrate them to Adonai.