1 Chronicles 23:6, 25, 26, 27, 28, 29, 30, 31

David separated the Levites into divisions corresponding to the sons of Levi: Gershon, Kohath and Merari.

For David had said, “Since the LORD, the God of Israel, has granted rest to his people and has come to dwell in Jerusalem forever

the Levites no longer need to carry the tabernacle or any of the articles used in its service.”

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

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.

They were in charge of the bread set out on the table, the special flour for the grain offerings, the thin loaves made without yeast, the baking and the mixing, and all measurements of quantity and size.

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

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