The Levites were earlier singled out for their failure to preserve the purity of the altar, and for failing to offer pure instruction. The priests were failing to give good leadership to the people, and had to take a large portion of blame. If there is going to be any “purification” among the people of Israel, it must begin with the spiritual leaders, that is, the Levites.
3 He will sit as a refiner and purifier of silver, and he will purify the sons of Levi and refine them like gold and silver, and they will bring offerings in righteousness to the LORD.