A lot of Christians are under the impression that a particular “hell” mentioned in certain Bible versions is a reference to the lake of fire, specifically the “hell” that is mistranslated from the word “Gehenna” (as opposed to the “hell” that is mistranslated from the words “sheol/hades,” or the other “hell” that is mistranslated from the word “tartarus”), and that some people will suffer forever in that place. Now, it is entirely possible that Gehenna will be the location of the lake of fire (and, in fact, I tend to think it’s likely that it will be), but if the lake of fire is in the same location that Jesus’ references to the worm that “dieth not” and the fire that is “not quenched” will take place in, this actually makes the doctrine of Infernalism (the idea that some people will suffer everlasting torment) even more untenable.
Even before going into all the details on what Jesus was talking about in His references to Gehenna, we already know that the only way to suffer forever in the lake of fire is to first be given an immortal body (remember, the lake of fire is a place that biological humans will be cast, after they’ve been resurrected from the dead, at the Great White Throne Judgement), and only those who have experienced salvation will have been made immortal at that time, making it impossible for someone who hasn’t experienced salvation yet to continue existing consciously in the lake of fire after they’ve burned up. So if Gehenna is where the lake of fire will be located, it remains impossible for it to be somewhere that any human could suffer in forever. However, while that right there is enough to prove that nobody will suffer forever in the lake of fire, it’s still helpful to look a little deeper at what else Scripture says about Gehenna.
Now, one of the keys to understanding Jesus’ teachings is to remember that, when He talked about the future to His audience, all possible outcomes for people (whether positive or negative) will take place in this physical universe rather than in an ethereal afterlife realm for ghosts. The kingdom of heaven has a spiritual aspect to it as well, but it was mainly a reference to an actual kingdom that will exist here on earth (specifically in Israel) in the future. And as far as His negative “threats” go, His primary one was about a place called Gehenna (γέεννα/Geenna in the original Greek), also known as the Valley of Hinnom (or the Valley of the son of Hinnom, depending on your Bible version), which was an actual, physical valley in Israel (and not in another dimension one enters after death), and Jesus’ Jewish audience would have immediately recognized it as a reference to Isaiah’s prophecy about the place the corpses of lawbreakers here on Earth would be burned up and devoured by worms in — although it’s actually quite pleasant at the moment.
I really don’t know how, but somehow almost everybody has failed to notice the word “carcases” in the passage in Isaiah that Jesus was referencing, missing the fact that he was writing about dead bodies which living people would be able to see in the future on Earth rather than about conscious souls in some afterlife dimension, and that Jesus would have then been speaking about the same thing that Isaiah wrote about. Now, the worst punishment a Jewish person could experience after death was to be denied a proper burial (there couldn’t be a worse consequence than that because most Jews believed that one ceased to exist consciously after death, which is what Scripture also teaches, as I’ve covered elsewhere on this site), which is why cremation is forbidden for Jews to this day for the most part. In fact, Jews are basically obligated to bury any and all corpses, even if it’s the body of a criminal who had been put to death, so to be told that they not only might be kept from living in the kingdom of heaven when it begins on Earth but that they could potentially be left unburied and might instead have their cadaver unceremoniously cast into the most unholy place in all of Israel when the Millennium begins as well (the valley in which certain ancient Israelites burned their children to death as a sacrifice to the god Molech) would be the most humiliating indignity Jesus’ audience could have been threatened with.
So Jesus wasn’t threatening that anybody would be tortured in Gehenna; He was simply giving a warning that certain sins would result not only in death (or lack of resurrection if they’re already dead at the time) so that one couldn’t enter the kingdom of Heaven when it begins in Israel (and that certain sins during the Millennium will also have the same result), but also that they risked losing out on a proper burial so that their corpse would instead be seen burning up by everyone who looked upon it as well, which would be (and will be) a great source of shame before they die. Like Judas, it would have been far better for them to have died in the womb or in childbirth than to have been born at all, since babies who aren’t born never have to deal with such indignities (and are also far more likely get to live on the New Earth than Judas or any of those who will be cast into Gehenna are as well, at least prior to the consummation of the eons).
As far as the reference to the worm that “dieth not” goes, this isn’t talking about magical worms that never die (or about human souls not dying either, since we already know from Isaiah that the only people in Gehenna — which, again, is here on our physical planet and not in an afterlife dimension — will be in corpse form). The Greek word for worm there is “σκώληξ” (“skōlēx”), which refers to regular maggots, not to human souls, or even to mystical, immortal worms that chomp on the souls of sinners for eternity. To put it simply, it’s talking about living (conscious) creatures who consume dead (unconscious) bodies. Jesus and Isaiah were just saying that any dead body that will be thrown into the valley will be totally consumed, either by maggots or by fire. And while it is technically true that the “worms” won’t die, that’s just because maggots are simply larval flies which go through a process known as pupation and grow into adult flies, so they won’t die while still in their larval, “worm” form but will instead grow up and lay eggs so that there are then more “worms” to consume more of the bodies in the valley. That said, the idea that something or someone “would not die” is used in various other parts of Scripture as well, but they did still eventually die, so it’s important to realize that this phrase doesn’t mean the thing said to “not die” never will; it just a figure of speech that means it won’t die before it’s supposed to.
Likewise, the fire that “isn’t quenched” (“quenched” being a word that just means it won’t be deliberately put out, not that it can’t go out on its own once it runs out of fuel) will burn for as long as there is fuel (primarily consisting of dead bodies) to keep it burning. But, just like the fire on the altar in Leviticus that was said to never be quenched but is no longer burning (among other things Scripture says will not be quenched but eventually stop burning), it will also eventually go out.
Thanks to certain bad translations of Scripture, as well as a simple lack of understanding of how these passages should be interpreted, Gehenna has been thought by most Christians to be referring to a place all non-Christians will go to suffer forever in after they die, when it really only applies to a very specific (and relatively small) set of people living in a very specific period of time that hasn’t even occurred yet (at least not as of the time this was written), and nobody will even be conscious in it, much less actually be suffering, since it’s a reference to a geographical location on Earth rather than to an afterlife realm.
Now, some Christians like to point out that, at the time Jesus used the word, some Jews might have used the word “Gehenna” figuratively to refer to a concept that one could loosely describe as the place we think of as ”hell” today. But even if that happened to be the case (and there is reason to believe that the usage of the word in this manner didn’t occur until after the Bible was written), the fact of the matter is that Jews in Jesus’ time believed all sorts of unscriptural ideas, many of which Jesus had to point out they were wrong to believe because the ideas weren’t found anywhere in the Hebrew Scriptures (“have you not read…?” is something Jesus sometimes had to say to them), and this would be one of those concepts that definitely wasn’t found anywhere in the Hebrew Scriptures (you’re welcome to try to find the concept of never-ending conscious torment in the Valley of Hinnom in the Hebrew Scriptures, but so far nobody has been able to show me an example of it being taught there).
And as far as the fate of anyone whose corpse is burned up in Gehenna during the Millennium goes, it’s the same fate as anyone else who hasn’t experienced salvation (meaning been made immortal and sinless) at that time. They’ll be resurrected into physical, mortal bodies, and they’ll be judged at the Great White Throne, and some of them will even end up being cast into the lake of fire to die and be burned up a second time. Which means that, if the lake of fire is going to be located in Gehenna, the same thing will happen to them the second time they end up there that happened to them the first time they ended up there: they’ll simply burn up. But, just like everyone else, they’ll also eventually be resurrected, and this time to immortality.
As for why I personally suspect that the lake of fire will be located in Gehenna, there are a couple reasons. The first is because I’ve noticed that the passage almost immediately prior to the reference in Isaiah to the undying worms and unquenchable fire is a statement that implies this will take place at least partly on the New Earth (although we have to keep the mountain and valley aspect of prophecy in mind, since we know that part of it will be during the Millennium as well, but that Isaiah just wasn’t likely aware of that fact), and it seems unlikely that there would be two places for burning corpses on the New Earth (a place called Gehenna and a place called the lake of fire) after the Great White Throne Judgement takes place. But similarly, we know that the beast and the false prophet (well, almost certainly actually the evil spirits who possessed the two humans who went by those titles, with the humans simply dying and being burned up) will be in the lake of fire during the Millennium, and the similar point that it seems unlikely there would be two places for burning corpses in Israel in during the Millennium would apply here too. So it does seem likely that they’re one and the same place, which I actually see as being very beneficial to our doctrines since it means that the place which is often mistranslated as ”hell” in certain Bible versions can’t be in an afterlife realm, but can only refer to a place here on our physical planet where biological, mortal humans will end up, and everything I wrote about human immortality equalling salvation, and about the reference to corpses in Gehenna in Isaiah, means that nobody can actually suffer there any longer than it takes to die from being burned up in fire, telling us that nobody will actually suffer forever in the “hell” that Infernalists like to talk about.