“Jehoiada assigned the care of the house of Yahweh to the Levitical priests. King David had organized the Levites to be in charge of the house of Yahweh. They were to offer burnt offerings to Yahweh, as it is written in the Law of Moses, with rejoicing and singing, according to the order of King David. He stationed the gatekeepers at the gates of the house of Yahweh so that no one should enter who was in any way unclean.”
This is loosely based on 2 Kings, chapter 11. The priest Jehoiada seemed to be in charge in this theocracy. To be safe, Jehoiada set up Levite gatekeeper guards around the temple of Yahweh, just in case there was any retaliation. All the positions of the Levites were to be according to the order of King David and the Mosaic Law when sacrificing burnt offerings.