I can't speak for other religions, but I'm pretty sure Catholicism doesn't actually require belief to go to heaven--more of the good works category. Belief is good, and supposedly makes it easier to be good, but is not necessary. This, I think, is a more recent change in catechism, which says that anyone can go to heaven as long as they live good lives, regardless of belief (Yeah, I understand that the new pope botched this, but it still applies anyways).
In contrast, if you believe in God but do bad things, then you would still be punished.
Of course, there isn't a whole lot of talk about hell either, mainly its accepted that unless you're exceptionally good or exceptionally bad, you'll go to purgatory, which is like hell, but only temporary.
To sum it up: doing good works in the name of the devil counts as God's work while doing bad things in the name of God counts as the devil's work.
ETERNAL QUEEN OF HALLOWEEN STATUS CONFERRED. ~ Comrade Pants
How can we be sure that Alcoremortis isn't just Comrade Pants trollplaying as a girl? ~ GuruGuru214
You're a shiny bright star; floating amongst a million slimy slugs in a sea of sludge. You transcend the pre-conceived and supposed limits of the human race, to emerge from the pit of pitiful maggots as a beautiful, majestic butterfly. ~ Davies
The suspence of what's gonna come after death is killing me! ~ Jon NA
Are you a secret Plaster Princess or something? ~ Secret Fawful