2 Chronicles 30:13-15

13So a huge crowd assembled at Jerusalem in midspring to celebrate the Festival of Unleavened Bread.

14They set to work and removed the pagan altars from Jerusalem. They took away all the incense altars and threw them into the Kidron Valley.

15On 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.