Malachi 3:2-3

But who will be able to endure the day when he comes? Who will be able to survive when he appears? He will be like strong soap, like a fire that refines metal. He will come to judge like one who refines and purifies silver. As a metalworker refines silver and gold, so the LORD's messenger will purify the priests, so that they will bring to the LORD the right kind of offerings.