Malachi 3:3-4

"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. Then shall the offering of Judah and Jerusalem be pleasant unto the LORD, as in the days of old, and as in former years" - Malachi 3:3-4 KJV