2 Chronicles 31:2

And Hezekiah appointed the courses of the priests, and the
Levites after their courses
As they were fixed by David, and were in the times of Jehoshaphat, and had been since interrupted, and which Hezekiah now restored, and placed them in their regular order:

every man according to his service, the priests and Levites for
burnt offerings, and for peace offerings, to minister and to give
thanks, and to praise in the gates of the tents of the Lord;
or camp of the Lord, where they were posted, and lay as an host encamped, to keep the watch of the house of the Lord; the priests, they were appointed to offer the sacrifices of every sort; the Levites to minister to them in what they needed and required of them, and others of them to be singers in time of service, and others to be porters at the gate.