1 Chronicles 23:30-32

30and to stand every morning to thank and praise Jehovah, and likewise at even; 31and to offer all burnt-offerings unto Jehovah, on the sabbaths, on the new moons, and on the set feasts, in number according to the ordinance concerning them, continually before Jehovah; 32and that they should keep the charge of the tent of meeting, and the charge of the holy place, and the charge of the sons of Aaron their brethren, for the service of the house of Jehovah.