First Read And Then Believe
I believe in God because there is logical reasoning that clearly makes sense. You said:“if light is present, we conclude that there must be a source producing that light, whether or not we can directly see the source itself.” If you explicitly claim with 100 percent certainty that the light is being produced by someone holding a torch, and that there is absolutely no other possible source, then logically we would ask: How do you know that the source of the light is someone holding a torch? Just the same way, how do you know with 100 percent certainty that whoever is making the claim about preservation and the fate of Bani Israel is God and not Muhammad himself, when this valid possibility exists too?