2 Chronicles 29:15, 34

These men called together their fellow Levites, and they all purified themselves. Then they began to cleanse the Temple of the LORD, just as the king had commanded. They were careful to follow all the LORD’s instructions in their work.

But there were too few priests to prepare all the burnt offerings. So their relatives the Levites helped them until the work was finished and more priests had been purified, for the Levites had been more conscientious about purifying themselves than the priests had been.