1 Chronicles 23:27-32

27 According to the last instructions of David, the Levites were counted from those twenty years old or more.

28 The duty of the Levites was to help Aaron’s descendants in the service of the temple of the Lord: to be in charge of the courtyards, the side rooms, the purification of all sacred things and the performance of other duties at the house of God.

29 They were in charge of the bread set out on the table, the flour for the grain offerings, the unleavened wafers, the baking and the mixing, and all measurements of quantity and size.

30 They were also to stand every morning to thank and praise the Lord. They were to do the same in the evening

31 and whenever burnt offerings were presented to the Lord on Sabbaths and at New Moon festivals and at appointed feasts. They were to serve before the Lord regularly in the proper number and in the way prescribed for them.

32 And so the Levites carried out their responsibilities for the Tent of Meeting, for the Holy Place and, under their brothers the descendants of Aaron, for the service of the temple of the Lord.