south carmain wrote: the Criteria is rather simple as far as Christian theology goes, we are all sinners therefore we all deserve the wrath of god and none deserve to enter paradise, but out of love Jesus was sent to earth to sacrifice himself to take upon himself the wrath of god and absolve us of our sins that we may be purified and enter paradise which is a place of perfection therefore no one who hasn't been cleansed by the blood of Christ may enter as they are still "dirty" by sin.
That's the short version anyway but of course you really need to study in detail both the old and new testament to understand the full picture as it's a very deep philosophical concept.
It would be simple if not for the fact that in order to be saved you have to accept Jesus in your life and we are talking about a just God. Wouldn't it be unfair for those who never even heard of Jesus or have been dead before his sacrifice took place? Are Adam and Eve forever doomed because of an Angel created by God?
Are our salvation a matter of luck in meeting a missionary to learn and accept the Bible and Jesus during our lifespan?