Just out of curiosity, why wouldn’t you believe what God says is so? Why bother to believe in Him if you believe that what He says is untrue?
I believe in God based on logic and personal experience. I don’t believe in revealed religion. I believe we have an innate ability to communicate with God in some way we can’t understand, and we really can’t possibly understand God. So when we do, people put it into the context of their own culture and knowledge of the world and existing mythology. IMHO that’s where revealed religion comes from.
In short, God is God, religion is what people say about God. You may argue that religion is what God says about God, but at most only one can be. If yours is right, the rest must be made up by men.
I don’t attack people who choose to believe in a particular revealed religion, but if someone says you can’t believe in God without believing in their particular brand of revealed religion I have to respond.