An interesting response - thank you.
I think it is probably helpful to separate out:
- Christianity the faith (based on the Bible / personal relationship with God / etc.
- Christianity the religion (man-made / the way the church has grown and added control / not of the Bible / etc.)
I refer to Christianity the faith - while most people would see Christianity as a religion - and there is absolutely a religion of that name, it is the one belief system which technically should not be a religion because we are not asked to take steps / jump through hoops / have structure etc. to 'get to the goal'. It is a faith because it is about belief / acceptance / repentance / relationship, not rules and regulations - Jesus was very clear that he came to replace those because they were not working - people (e.g. Pharisees) simply added to them and invented new ones, Judaism became a religion of ticking boxes which totally lost the point that God made us to be in relationship with him - so Jesus came to reset that and allow us access to God simply through repentance and accepting Jesus' death on the cross.
As such, Jesus' death removed the need for any task completion / box ticking / rule observation with a one-off moment when he died for us. We see in the gospel of John:
"16 For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life.17 For God did not send his Son into the world to condemn the world, but to save the world through him.18 Whoever believes in him is not condemned, but whoever does not believe stands condemned already because they have not believed in the name of God’s one and only Son."
real clarity around what Christianity is - in reductive form:
- God loved us all
- God gave up his son for us
- whoever believes shall not perish / will have eternal life / is not condemned
All that is required of us is to believe - as verse 18 confirms, whoever believes in him is not condemned - that is it, absolute and certain - believe - job done.
Every religion on the planet has more than that - it has rules and regulations to follow which mean that you achieve something - whether it is prayer or knowing scripture, or food rules, or giving of money - do xyz to get to heaven / equivalent. (The Christian religion - man made bits - may also have this, but that is not biblical, is not of God, is not a requirement).
The Christian faith quite simply is unique - it turns the concept on its head and says that God loves us so much that rather than expecting us to be able to do this - he chose to take the burden on himself and sent his son to die for us - i.e. instead of our paying the price by doing xyz - God wants a relationship with us so much that he paid that huge price for us all - once and forever.
With other religions - is there a question to ask - if their god wants us to be with him - why are barriers put in our way - you could argue it is to prove ourselves worthy, but no human could ever achieve that level, so all it does is help people to fail - but God isn't the same - He chooses to be in relationship with us and went literally to Hell and back to achieve it so that we don't have to do anything more than accept it
Furthermore, once we believe and accept Christ dying for us - there is arguably a whole New Testament telling us what to do (faith v works argument) - but yet again, Christianity is a topsy turvy 'religion' - rather than doing those things to be a Christian / stay a Christian - there is a real clarity that it is because we are a Christian and in relationship with God, we will want to do those things - so they are the natural outfall of walking every day with Jesus, rather than pre-cursors to being accepted by a God with a clipboard.
There have absolutely been those through history (and even today) who add their own rules onto Christianity (as you mention, buying indulgences / prayers / monetary gifts / etc. are all examples) - however none of that is Biblical, none of that is Christianity - despite people making that claim / using the Bible to find words out of context to support their desires / greed - the Bible has absolute clarity (from the above):
Whoever believes in him, is not condemned...
It really is that simple, that easy, that quick - genuine acceptance of Jesus's death, repentance of our previous life / sins - that gives us access to a relationship with God on earth and then for eternity in Heaven...
24 “Very truly I tell you, whoever hears my word and believes him who sent me has eternal life and will not be judged but has crossed over from death to life. (John 5:24)
another passage - confirming that all we need to do is hear and believe and we at that moment will no longer be judged, but now have eternal life, not will in the future cross over from death to life - but has crossed over - job done.
i.e.
say sorry
say thank you
say yes please
there is absolutely no other 'religion' which has that simple, that clear, that black and white an offer for eternal salvation (eternity in heaven as per the original OP's post) and which requires no actions from the individual other to believe and accept it...