You’re confusing faith with religion.
Simply put, religion is social engineering. Its function is to show us how to get along together, and how to deal with the bad stuff. Unfortunately, that’s a bit boring. We all know that we should be nice to each other, and we know we should have rules to deal with the not-nice people and things. Apes, lions, dolphins, and other animals have highly-ritualised behaviours that do the same things. The difference is, humans have some spare cognitive capacity over and above ritual, and quite often, that spare capacity gets used for being mean and doing bad things. If we tried to rely on those simple ritualised principles to survive, we’d have died out millennia ago, because we’d muck about and subvert them.
So, some very smart people – not necessarily the famous prophets – at various times and in various places codified those basic principles as religions. The difference was, religions usually had a god or a pantheon who demanded you follow these principles on pain of roasting for eternity, being cast into the beyond, or reincarnating as a dung beetle. They also handed out rewards for good behaviour, mostly after you died. Amazingly, despite – or maybe because of – our arrogance and superiority, we were okay with there being an even more powerful entity than us. Even more amazingly, we’d do things for the approval of these entities that we’d never do for our leaders or loved ones.
And that’s faith. Not the rules, but the belief in the rules.
Ultimately, simple rules are seen as too simplistic. Sure, you can be nice to everyone, BUT what if you’ve only got a single coin for alms, but two people in need ask for your coin. Who do you choose to give the coin to? How do you decide whose need is greater, person A, person B – or you, since you’ve only got this one coin? Suddenly the principle isn’t enough, and you have to introduce codicils and judgements. And the more complicated and vague the rules got, the more we clung to them.
That’s where faith starts going down different roads, tracking the same basic principles through to differing conclusions.