Refiner

Boyd’s Bible Dictionary:

(who makes fine). A worker in precious metals (Isa. 1:25²⁵And I will turn my hand upon thee, and purely purge away thy dross, and take away all thy tin: (Isaiah 1:25); Isa. 40:10¹⁰Behold, the Lord God will come with strong hand, and his arm shall rule for him: behold, his reward is with him, and his work before him. (Isaiah 40:10); Jer. 6:29²⁹The bellows are burned, the lead is consumed of the fire; the founder melteth in vain: for the wicked are not plucked away. (Jeremiah 6:29); Zech. 13:9⁹And I will bring the third part through the fire, and will refine them as silver is refined, and will try them as gold is tried: they shall call on my name, and I will hear them: I will say, It is my people: and they shall say, The Lord is my God. (Zechariah 13:9); Mal. 3:3³And he shall sit as a refiner and purifier of silver: and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the Lord an offering in righteousness. (Malachi 3:3)).

Concise Bible Dictionary:

God is the refiner of His people, as the precious metals have to be separated from the dross that clings to them (Prov. 25:4⁴Take away the dross from the silver, and there shall come forth a vessel for the finer. (Proverbs 25:4)—where the AV has “finer”; Isa. 48:10¹⁰Behold, I have refined thee, but not with silver; I have chosen thee in the furnace of affliction. (Isaiah 48:10); Zech. 13:9⁹And I will bring the third part through the fire, and will refine them as silver is refined, and will try them as gold is tried: they shall call on my name, and I will hear them: I will say, It is my people: and they shall say, The Lord is my God. (Zechariah 13:9); Mal. 3:2-3²But who may abide the day of his coming? and who shall stand when he appeareth? for he is like a refiner's fire, and like fullers' soap: ³And he shall sit as a refiner and purifier of silver: and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the Lord an offering in righteousness. (Malachi 3:2‑3)). So God tests the believer’s heart (1 Thess. 2:4⁴But as we were allowed of God to be put in trust with the gospel, even so we speak; not as pleasing men, but God, which trieth our hearts. (1 Thessalonians 2:4)), and his faith, which leads to endurance (James 1:12¹²Blessed is the man that endureth temptation: for when he is tried, he shall receive the crown of life, which the Lord hath promised to them that love him. (James 1:12); 1 Pet. 1:7⁷That the trial of your faith, being much more precious than of gold that perisheth, though it be tried with fire, might be found unto praise and honor and glory at the appearing of Jesus Christ: (1 Peter 1:7)).