When responding to, “What about the unquenchable fire in Mark 9:48?” we need to realize that Jesus is quoting verbatim Isaiah 66:24 in this passage so please read, Why rarely cited Isaiah 66:24 is a key for a more complete understanding of this scripture. Proper hermeneutics demands that we interpret scripture with scripture…including Mark 9:48. If Jesus is quoting Isaiah, shouldn’t we read Isaiah too? Obviously Jesus would not disagree with Isaiah. Was Isaiah talking about the soul? Clearly he was not.
Second of all, if God throws something into eternal fire, who says that what is thrown in, is eternal also? Inter-Varsity Press author John R. Stott rightly concludes:
“…it would seem strange…if people who are said to suffer destruction are in fact not destroyed…it is difficult to imagine a perpetually inconclusive process of perishing.”
(J. Stott and D. Edwards, Essentials: A Liberal-Evangelical Dialogue, London: Hodder & Stoughton, 1988, p. 316)
Third of all, this phrase in Mark 9:48 is used elsewhere in “Tenach” (the Old Testament) and is never used to mean eternal torment. If you look up Isaiah 66:24, Jeremiah 7:20 and 17:27, and Ezekiel 20:47-48, they all mention that same phrase. And reading the context of these verses, it can clearly be seen that “unquenchable” means a judgment that man cannot “quench” or “talk God out of.” In other words, no one can talk God out of it and it will indeed run its course. Has God ever been “talked out of” something in the past? Yes. Clearly Moses talked God out of destroying Israel in the desert. (Exodus 32:10-14) In a real sense–Moses “quenched” God’s anger against Israel.
Fourth of all, remember it (the fire) was “prepared for the devil and his angels.” (Matt 25:41) It was never, never made for humans. Humans will perish in the fire, not be preserved in the fire. With that in mind, reread the second point above by John Stott.