2 Chronicles 29:15, 34

These Levites gathered their brothers together and made themselves holy for service in the Temple. Then they went into the Temple of the LORD to purify it. They obeyed the king’s command that had come from the LORD.

There were not enough priests to skin all the animals for the burnt offerings. So their relatives the Levites helped them until the work was finished and other priests could be made holy. The Levites had been more careful to make themselves holy for the LORD’s service than the priests.