The arguments generally revolve around the tension between justice and forgiveness.
Jumping to forgiveness elides the question of sins and crimes and injustices that demand punishment, atonement, reparation, consequences.
How can God welcome everyone into Paradise, oppressor alongside oppressed, murderer alongside murderer, rapist alongside their victims, and every other kind of perpetrator of evil and those they have trespassed against?
The Cross is meant as a way of reconciling this tension, and a great many sermons have been devoted to trying to explain the mystery of it.
Perhaps because existing answers are unconvincing to those asking :)
To that end:
> How can God welcome everyone into Paradise, oppressor alongside oppressed ... ?
Your god supposedly made this universe, and dictated the laws that govern it--metaphysical and otherwise. I have a difficult time making excuses for oddities in those laws alongside that.
From the outside, it all looks like a bit of a cup game [1]: We have sinned against god, and have been stained eternally by that. God demands punitive justice for our transgressions, yet we cannot redeem ourselves independently, by god's laws. The only way to wash the sin from ourselves is for god to send himself (which is also his son?) to die for our transgressions, satisfying this punishment (though he'll be raised 3 days later), such that we can then pass into his kingdom.
(1) Apologies for irreverence, this just sounds like when a bunch of 3 year olds are playing war in the yard:
"I shoot you with my laser!"
"Well my atomic armor blocks your laser!"
"But my laser is hooked up to my fusion backpack, and cuts through your atomic armor!"
(2) I don't understand how in any way this reforms us sinners that we may pass into heaven and exist alongside each other--we haven't undergone any transformation on our own such that we understand the terrible crimes we're supposedly guilty of; we're certainly (in the church's view) not any less likely to commit sin if we know about these crimes we've committed and the supposed significance that god himself had to die (but only kind of?) for them.
In either reformative or punitive justice, it makes no sense: we're no less likely to commit these sins by threat of punishment, because we can be forgiven simply by believing in Jesus. We also aren't any less likely to commit sin by being reformed because... we haven't reformed at all, we simply believe in this story.
I'd kindly request you to consider looking at this from a secular view, as if someone were proposing this as a system of justice in a secular context: Does this seem a reasonable way to structure a society, where those who break the laws of the society can send someone in their stead for reformation or punishment? I strongly doubt the efficacy of such a system, and I find it so strange that folks accept it in a religious context.
> The Cross is meant as a way of reconciling this tension, and a great many sermons have been devoted to trying to explain the mystery of it.
Perhaps god could have explained it more clearly and saved us all a lot of confusion :)
As it stands, I see no reason to believe this tension exists in the first place. In order for this explanation to make sense I first must subscribe to your premises--that god exists, that we're guilty of eternal sin which we're unable to address ourselves, etc--which I see no reason to do.
About 800 years before the birth of Christ the prophet Isaiah wrote the following prophecy (Isaiah 53:5-6):
"But he was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was on him, and by his wounds we are healed. 6 We all, like sheep, have gone astray, each of us has turned to our own way; and the Lord has laid on him the iniquity of us all."
I encourage you to read the the whole chapter of Isaiah 53 here:
https://www.biblegateway.com/passage/?search=isaiah+53&versi...
As Christians this is our salvation and what we believe when Jesus died and rose from the cross.
Happy Easter! :-)
Edit: Thought about it a little more and I guess fear is a pretty legitimate reason to do so. If one truly believes that if one does not worship then an eternity in hell is on the plate then worshipping does make sense but it cant be anything except a Stockholm syndrome style of worship.