2 Chronicles 35:15-16

15And the singers, the sons of Asaph, were in their place, according to the commandment of David, and Asaph, and Heman, and Jeduthun the king's seer; and the doorkeepers were at every gate; they had not to depart from their service, for their brethren the Levites prepared for them.

16And all the service of Jehovah was prepared the same day, to hold the passover, and to offer burnt-offerings on the altar of Jehovah according to the commandment of king Josiah.