2 Chronicles 35:15-16

15The musicians, the descendants of Asaph, were in the places prescribed by David, Asaph, Heman and Jeduthun the king’s seer. The gatekeepers at each gate did not need to leave their posts, because their fellow Levites made the preparations for them.

16So at that time the entire service of the Lord was carried out for the celebration of the Passover and the offering of burnt offerings on the altar of the Lord, as King Josiah had ordered.