Belief just means standing for something. I believe in generosity, self control, avoidance of violence, the proper treatment of women and children, etc etc. I’ll stand behind it regardless of what you say. The Qur’an also advocates this, and people agree with it so they “believe” in what’s written. Only believing in the Creator Himself and everything that happens after death requires any sort of “effort”, and even the former I would say is self evident!