2CH 29:34

34 But there were not enough priests to remove the skins from the animals that would be completely burned [on the altar]. So their fellow descendants of Levi helped them until that work was finished, and until other priests had purified/consecrated themselves to do that work. It was necessary for them to do that because many of the priests had not yet performed the rituals to consecrate themselves for that work, like the descendants of Levi had done.