Malachi 3:2-3

But who can endure the day of His coming? Or who can stand when He appears? For He will be like a refiner’s fire, and like soap for cleaning raw wool. And He will sit as a smelter or a purifier of silver, and He will cleanse the sons of Levi, and purify them like gold or silver. Then they will become for ADONAI those who present an offering in righteousness.