When I talk about exclusivism with Christians I generally just ask questions, rather than provide my own arguments I wait to see what they think themselves (a lot of Christians I've talked to said at first that they absolutely believed that only Christians go to heaven, but after a few quick questions they started realizing that they might not truely be so sure). Regardless of what the scripture says about whether you have to follow Christ to get into heaven (and it actually says things both ways in the new testament) and regardless of whether we're looking at a literal or non-literal interpretation of that scripture, I think these questions are good ones.
Like I said, I'm not out to try and change anyone's beliefs, and I don't expect these questions to change anyones beliefs. The purpose of these questions is simply to clarify for people what their own beliefs actually are.
These questions all have a single root question behind them, and that question is: if only by accepting Jesus as the son of God and truly opening your heart to him can a person get into heaven - when did/does this come into effect? Remember that before Jesus came this was not a requirement YHWH had laid down, according to Judaism the laws in the Tanakh (old testament) only applied to themselves as the chosen people, people of other religions were judged by YHWH on different criteria.
One: Did this requirement for getting into heaven start when Jesus started teaching, or when he died? (Not a very important question, but it slightly effects the later ones).
Two: Whichever of the above you chose, or if you're unsure, this question is the same: IF this requirement came into effect at a specific time, might that specific time only apply to a specific place? More specifically: after Jesus died (let's say that's what you picked for Q1), did everyone other than the tiny handful of Christians at the time in the entire world instantly start being condemned?
If you answered yes, everyone became condemned instantly dispite the fact that they had no way of having even heard of this Jesus fellow, then the questions end here. If you answered no, or unsure, proceed to question three.
Three Considering that Christianity would take several hundreds of years to spread much further than a thousand miles or so around the local area, and also considering that not only did the religion spread slowly but even just simply hearing about the religion would take many generations for the vast majority of the world (and would take even longer than 1500 years to reach some places) - might it make sense that God would have not put that requirement into effect on the entire planet all at once, but rather would have extended amnesty to those who hadn't even heard of Jesus?
If yes, then on to question Four: If you do think that it might have come into effect at different times depending on when people even had any chance whatsoever to fullfill it (can't believe in something you haven't heard of!), once word of Christianity reached an area, what specifically would trigger it coming into effect for that area?
To be more specific - does it come into effect for a village in India when the first wandering Muslim comes through and mentions this other religion that's similar to his own, but just mentions it in passing? Or does it not come into effect until someone who's actually educated in the religion shows up to teach people about it?
If we're answering yes to the need for an actual person of the religion to come, then on to one of the last questions, number Five: How long after this missionary arrives do people have to accept the religion? If someone dies while the guy is just starting to explain who Jesus was, are they possibly exempt, or are they condemned because they'd started to hear but hand't changed their mind? Regardless of that, do people get to sleep on the concept before converting, or must it be immediately? If they are allowed a few days to learn about it, then how long are we talking? A week, a year, a generation? If we've decided it doesn't make sense for God to exclusively let in Christians when others haven't heard of it, or are just finding out about it - is there any possible way of even remotely guessing how long those people are allowed to think about it before throwing away the religion they'd practiced for generations and converting to this new one, for no reason other than that some guy showed up and told them they had no choice but to convert or burn forever?
(Sorry for the length of that one, it's a lot of questions in one)
Last question: What if that missionary just wasn't convincing? Nobody in the village converted, but they didn't reject Jesus because they didn't like him, they simply just weren't convinced? After all, the guy from Islam was there last year and he did a really good job, the Buddhist who showed up the year before that got a few converts, and the Jainist did even better ( that's just for example, the point is that if 15 missionaries show up from different religions, and the Christian guy happens to be less convincing, are they all condemned basically because the guy failed his job?).
Now let's get to the point of all this and fast forward to today. There are still places where people have never even heard the name "Jesus", and beyond that, there are lots of places that are barely even exposed. And even if they are, how are those people supposed to pick the right religion out of all the ones presented to them, why not just keep believing in their own? Could that original amnesty period still be under effect for some people?
And I'll cheat and sneak in one more question. If you answered those questions in a way that made you question absolute exclusivism, might it be better to give God the benifit of the doubt that he knows what he's doing here (I'll call God a male for now...)? Maybe he wanted the Bible written just the way it was so that people would take that particular religion seriously, but maybe he knew all along that a lot of people would take a while, and he's got a plan for that (something about him being omniscient comes to mind here).
Just food for thought, like I said, I'm not out to convert people, just to make them think.
