“And He will sit as a smelter and purifier of silver, and He will purify the sons of Levi and refine them like gold and silver, so that they may present to the Lord offerings in righteousness” (Mal. 3:3). The smelter by fire skims off the impurities of silver. He knows it is pure when he can look into the molten metal and see his own face reflected as in a mirror. The fire of Pentecost is about the Spirit cleansing us for Christlikeness.
“And God, who knows the heart, testified to them giving them the Holy Spirit, just as He also did to us; and He made no distinction between us and them, cleansing their hearts by faith.” Acts 15:9