2 Chronicles 35:14-15

14Afterward, they made preparations for themselves and for the priests, since the priests, the descendants of Aaron, were busy offering up burnt offerings and fat until night. So the Levites made preparations for themselves and for the priests, the descendants of Aaron.

15The singers, the descendants of Asaph, were at their stations according to the command of David, Asaph, Heman, and Jeduthun the king’s seer. Also, the gatekeepers were at each temple gate. None of them left their tasks because their Levite brothers had made preparations for them.