The text declares that the Levites would be purified, but not how. The Lord could purify the hearts of the Levites (Psalm 5:10), through the Spirit’s work of inward sanctification. Or the Lord could purify the Levites by eliminating the corrupt priests, leaving a faithful remnant of Levites to lead God’s people.
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.