If someone is telling you to follow their religion, it is because they are convinced it is God-approved. But that's only because someone ELSE told them it was God-approved. And that person had someone in THEIR past tell them it was God-approved.
Which religion is Gandalf-approved? Which religion is Odie-approved? Which relgi--oh. What? You don't care what fictional characters approve of? Funny, neither do I.
Have you been struck with lightning from above? No? Then you're approved. Seriously, any religion or belief (and I include atheism) that leads its people to be kind and just to their fellow beings (including animals, not just humans) can't be that far wrong. So if your religion teaches you that, you are approved.
You can't know for 100% that your way of worship is approved by god. Since God is only a feeling and thoughts in peoples minds, you can only think he approves, but without evidence of his existence there is no evidence of his approval.
Religion and denomination are not the same thing #1. Religions are Christianity, Islam, Hinduism, Catholicism, Buddhism, etc. Denomination is where all the people love to fight over who is right. That's your Baptists, Methodists, Presbyterians, COGIC, Lutherans,
You don't... All christians, muslims, mormons, jews, and pagans are just following something blindly... No one has seen a god or gods... All you have are texts written by other people following their religion blindly...