2 Chronicles 35:14-15

14After this, they made preparations for themselves and for the priests, because the priests, the descendants of Aaron, were sacrificing the burnt offerings and the fat portions until nightfall. So the Levites made preparations for themselves and for the Aaronic priests.

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.