The issue with any of the passages referring to everlasting fires (generally translating gehenna), is that while the fires last forever, the passages never actually say that the person will “survive” in those fires forever. The point being that the more traditional Jewish belief is that those who have done evil will, themselves, be destroyed in the fires that never will die.
There are passages that talk about everlasting punishment, but they are generally separate from the passages that use the image of fire or gehenna and they also generally use some variant of the problematic Greek word aion (’[symbol]aiwn[/symbol]), that does not have the specific meaning that “eternal,” “everlasting,” or “forever” have in English. It can mean “long ages” or “an indefinite long period of time” or even just “an age.”
My point in my exchange with DtC was that I do not believe that it is a cut-and-dried fact that Christianity introduced the notion of everlasting punishment in the second century. It may have done so, but there are glimpses and foreshadowings in the Apocrypha (such as Enoch), and there are references in other New Testament passages, that the concept of everlasting punishment was sufficiently familiar to the audience, indicating that while it was not a mainstream belief, it was a belief that people would have recognized.
As an example, Matthew 25:46
The exact same word is used to identify the future of those who are evil and those who are righteous, '[symbol]aiwnion[/symbol], yet I never encounter anyone arguing that those who are saved will eventually die.
However, to repeat the point, above, the references to everlasting fire that we find do not actually say that those condemed will burn forever, only that the fires, themselves, will never be extinguished.
And, again, I am not asserting that the belief clearly was present. I only contend that the issue is not one of clear fact.