Symbolism, Imagery, Allegory
As Minecrafters know, smelting is a process of extracting a purified metal from a chunk of metal ore or rock. It involves lots and lots of heat; the fire burns up the impurities. Smelting seems to be God’s favorite metaphor for what he has to do for the raw material of miserable sinners in order to end up with an ethically decent and obedient bunch of followers. When God smelts, it’s judgment time.
But who can endure the day of his coming, and who can stand when he appears? For he is like a refiner’s fire and like fullers’ soap he will sit as a refiner and purifier of silver, and he will purify the descendants of Levi and refine them like gold and silver, until they present offerings to the LORD in righteousness. (NRSV Malachi 3:2-3)
And I will put this third into the fire, refine them as one refines silver, and test them as gold is tested. They will call on my name, and I will answer them. I will say, “They are my people”; and they will say, “The LORD is our God.” (NRSV Zechariah 13:9)
It’s usually a small remnant of the people that are left after the smelting—God’s after quality, not quantity.