I wrote this on the city-data forum a while ago. Reposting as it is relevant here:
To understand the truth of universal salvation, one must begin to understand what these verses on Gehenna are really talking about. Its not an eternal hell of suffering and torment. It could be a reference to the lake of fire (but that is debatable even amongst those who believe UR).
What Jesus meant about Gehenna
Gehenna which is translated as "hell" in some bibles, was the literal valley of Hinnom near Jerusalem where garbage and dead bodies of criminals were burnt up. Jesus used the word "gehenna" as a symbol of judgment: It was very dishonorable to be thrown there, it meant you were a criminal not worthy of a proper burial. If you want to understand what Jesus was saying, we should look at the first place He talks about Gehenna, in Matt 5:22 (and Mark 9, etc):
Matt 5:22 But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire [gehenna].
Do you know what "Raca" means? It is talking about an insult. If you insult your brother, you get judgment from the council. BUT if you call a brother a fool, you could go into hell fire. WHAT? HELLFIRE? Does that make sense? Insulting leads to judgment at a council, but calling someone a fool (which is also an insult) leads to HELLFIRE?
NO. The word there for "hell fire" is actually gehenna. This is actually a mistranslation. You can see how this mistranslation renders this verse to nonsense. The correct meaning there is "gehenna", which in this case simply means another type of judgment - a common judgment of the time of Jesus.
No one is going to "hell" for calling their brother a fool, yet that is what the faulty KJV translation implies (faulty in this one verse at least).
The context of this passage is important. Jesus is talking to His disciples, believers - during the sermon on the mount. Jesus is talking about judgment and what one should do in certain situations:
Matt 5:21`Ye heard that it was said to the ancients: Thou shalt not kill, and whoever may kill shall be in danger of the judgment; 22but I -- I say to you, that every one who is angry at his brother without cause, shall be in danger of the judgment, and whoever may say to his brother, Empty fellow! shall be in danger of the sanhedrim, and whoever may say, Rebel! shall be in danger of the gehenna of the fire.
So we can see these are all different types of judgment:
- killing will lead to a judgment
- likewise with hating a brother (angry without cause - hating is just as bad as killing)
- insulting a brother -> leads to judgement at the council of the sanhedrim
- calling a brother a fool (or "Rebel!") could lead to being thrown into the valley of hinnom
In those days criminals were thrown into gehenna (the valley) as their judgment. These were all judgments that would happen to them in their life (not in some fiery afterlife). Its speaking about consequences for actions.
[NIV] 23"Therefore, if you are offering your gift at the altar and there remember that your brother has something against you, 24leave your gift there in front of the altar. First go and be reconciled to your brother; then come and offer your gift. 25"Settle matters quickly with your adversary who is taking you to court. Do it while you are still with him on the way, or he may hand you over to the judge, and the judge may hand you over to the officer, and you may be thrown into prison. 26I tell you the truth, you will not get out until you have paid the last penny.
So here we see Jesus is teaching us to be reconciled to our brother and fellow man. If we wish to murder or hate or insult our brother, we should stop what we are doing and go and be reconciled with him instead. Settle the matter with you adversary quickly.
This is all about settling disputes, and has absolutely nothing to do with a literal eternal torment in fire. This whole passage should be our first clue that "gehenna" is not "eternal hell".
So based on Jesus OWN words, we can see that Gehenna is simply talking about judgment, NOT eternal hell fire.
Again, its helpful to remember what judgment is for: setting things right - teaching righteousness.