In the Christian faith: God gave just 10 rules/commandments via Moses. The Jewish religious heirarchy greatly expanded upon those, creating hundreds of rules, but I digress. Those original 10 commandments were meant to show us that we are inadequate. If you could keep them in heart, mind and deed you’d be perfect. Apart from Jesus, to my knowledge, no one has kept them. The logical conclusion is that if God requires perfection, then He must save us. We cannot save ourselves. That’s where grace through faith comes in. We have faith in God/Jesus and he graciously forgives us and allows us to be with Him for eternity.

To me, that God exists is obvious. Knowing who God is, is more difficult. Different cultures identify with God differently. According to the Bible, Jesus is the only way to the Father/God. You cannot earn your way into Heaven by being good. I know many disagree with that concept, but that is what it says. No rules, just faith.