2 Chronicles 35:15-16

15The musicians, the descendants of Asaph, manned their posts, as prescribed by David, Asaph, Heman, and Jeduthun the king’s prophet. The guards at the various gates did not need to leave their posts, for their fellow Levites made preparations for them.

16So all the preparations for the Lord’s service were made that day, as the Passover was observed and the burnt sacrifices were offered on the altar of the Lord, as prescribed by King Josiah.