2 Chronicles 23:18-19

Then Jehoiada chose the priests, who were Levites, to be responsible for the Temple of the LORD. David had given them duties in the Temple of the LORD. They were to offer the burnt offerings to the LORD as the Teachings of Moses commanded, and they were to offer them with much joy and singing as David had commanded. Jehoiada put guards at the gates of the Temple of the LORD so that anyone who was unclean in any way could not enter.