And he shall sit as a refiner and purifier of silver: and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the LORD an offering in righteousness. He shall sit as a refiner - Alluding to the case of a refiner of metals, sitting at his fire; increasing it when he sees necessary, and watching the process of his work.
The sons of Levi - Those who minister in their stead under the New covenant, for the Old Levitical institutions shall be abolished; yet, under the preaching of our Lord, a great number of the priests became obedient to the faith, Acts 6:7; and, as to the others that did not believe, this great Refiner threw them as dross into the Roman fire, that consumed both Jerusalem and the temple.