2 Chronicles 29:33-34

33They also brought 600 bulls and 3,000 sheep to offer to the Lord.

34But there were not enough priests to prepare all the animals for the sacrifices. So their relatives, the Levites, helped them until they had finished the work. By that time more priests had made themselves clean to serve the Lord. (The Levites had been more careful than the priests to make themselves clean for the Lord.)