2 Chronicles 35:14-15

14Then afterward they prepared portions for themselves and for the priests, because the priests, the sons of Aaron, were busy in offering burnt offerings and fat until night; therefore the Levites prepared portions for themselves and for the priests, the sons of Aaron.

15And the singers, the sons of Asaph, were in their places, according to the command of David, Asaph, Heman, and Jeduthun the king’s seer. Also the gatekeepers were at each gate; they did not have to leave their position, because their brethren the Levites prepared portions for them.