Jesus never uses the word hell. The word hell didn't even exist. Jesus uses the word Gehenna. Or to be more accurate, in the manuscripts we have which claim to contain Jesus' words, the word Gehenna is used to refer to that place of weeping of gnashing of teeth. Gehenna translates directly into "The Valley of Hinnom", a place outside of Jerusalem that was basically the city dump.

So, for example, Matthew 18:9 would more accurately read:
"It is better for you to enter life with one eye than to have two eyes and be thrown into the fires of the Valley of Hinnom."

At that point it becomes extremely important for us to study not just what the Valley of Hinnom really was, but what meaning it had to the people Jesus was talking to. If you were a Jew living in Jesus' time, what would the implications of being thrown into the Valley of Hinnom be? Was this something that literally occurred? Was being thrown into the city dump a type of punishment? Was this a place people were banished to for a period of time or for ever? Was it a colloquialism whose real meaning is lost in time? Was it a symbol they would have understood or would his words have been a mystery even to them?

There are answers to all of those questions, some of them more conclusive than others. But the point I'm trying to make is that it isn't as clear as we may have been led to believe.