Matt 3:7-12: “But when he saw many of the Pharisees and Sadducees coming to his baptism, he said to them, “Brood of vipers! Who warned you to flee from the wrath to come?
Therefore bear fruits worthy of repentance, and do not think to say to yourselves, ‘We have Abraham as our father.’ For I say to you that God is able to raise up children to Abraham from these stones.
And even now the ax is laid to the root of the trees. Therefore every tree which does not bear good fruit is cut down and thrown into the fire.
I indeed baptize you with water unto repentance, but He who is coming after me is mightier than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire. His winnowing fan is in His hand, and He will thoroughly clean out His threshing floor, and gather His wheat into the barn; but He will burn up the chaff with unquenchable fire.””
Is John referring to people or to their works/faith? He does not say “Holy Spirit OR fire” – it is both, performing a true inward purification. It is easy to get a water baptism but the real test is a fire baptism which tests the true purity of our motives.
Buy WHY burn the chaff and not just let it be? WHY burn the trees that produce bad fruit? Because God wants us to bear fruit that is good and lasting (Psalm 1:1-3) and He wants to rid us from bad fruit or character – using the ‘cleansing’ fire to accomplish just that.
So the Holy Spirit carries a box of matches and sets fire to your life, and shows you what burns away and what is left, continually helping you to build with gold, silver, precious stones and not with wood and hay (1 Cor 3:10-15).
The unquenchable fire refers to the intensity of the fire and not the continuous nature of it.
Baptism comes from the Jewish ‘Mikveh’ which is an outward ritual that symbolizes inward change. So items or people become unclean and can only be made clean again by either living water or fire (Numbers 31:23). So water does not destroy anything but fire destroys that which is not pure.
1 Peter 1:7 speaks about the Refiner and its fire. Our faith is responsible for our actions (James 2:14-17). Our faith determines our fruit – bad faith, bad fruit and visa versa.
Some more verses about the refining fire in believers’ lives: Daniel 11:35, 12:10; Jeremiah 6:27-30; Isiah 48:9-11; Malachi 3:2-4
Refining of metals: The lake of fire, the added detail of “sulfur/brimstone” in the lake of fire is related to an ancient gold refining technique. Gold refining by sulphurization, also related to gold parting, is described in detail by ancient writers. When unwanted metals, such as lead and copper, are heated in the presence of sulfur, the chemical reaction reduces the unwanted metals into sulfides, such as lead(II) sulfide and copper(I) sulfide. Since sulfur is a much lighter element, atomic number 16 on periodic table, the new sulfide molecules easily float to the top of the crucible as dross. Sulfur is also part of the smelting process related to silver and gold and other metal ores and naturally occurs in these ores.