On the fourteenth day of the second month, one month later than usual, the people slaughtered the Passover lamb. This shamed the priests and Levites, so they purified themselves and brought burnt offerings to the Temple of the LORD .
References for 2 Chronicles 30:15
Then they took their places at the Temple as prescribed in the Law of Moses, the man of God. The Levites brought the sacrificial blood to the priests, who then sprinkled it on the altar.