'Refiner' in the Bible

And who is bearing the day of his coming? And who is standing in his appearing? For he is as fire of a refiner, And as soap of a fuller.

And he hath sat, a refiner and purifier of silver, And he hath purified the sons of Levi, And hath refined them as gold and as silver, And they have been to Jehovah bringing nigh a present in righteousness.