1 Chronicles 23:30-32
30 They are also to stand every morning to give thanks and praise to the Lord, and likewise in the evening.
31 Whenever burnt offerings are offered to the Lord on the Sabbaths, New Moons,(A) and appointed festivals, they are to do so regularly in the Lord’s presence according to the number prescribed for them.(B)
32 They are to carry out their responsibilities for the tent of meeting, for the holy place,(C) and for their relatives, the sons of Aaron,(D) in the service of the Lord’s temple.”