1 Chronicles 23:30-32

30to stand every morning to thank and praise the Lord, and likewise at evening;

31and at every presentation of a burnt offering to the Lord on the Sabbaths and on the New Moons and on the set feasts, by number according to the ordinance governing them, regularly before the Lord;

32and that they should attend to the needs of the tabernacle of meeting, the needs of the holy place, and the needs of the sons of Aaron their brethren in the work of the house of the Lord.