Everyone knows that Buddha Gautama was not a god or supernatural being. He lived a human life and discovered a way of achieving true wisdom and freedom from suffering. His teaching became a basis for Buddhist religion and brought essential knowledge to people seeking conciliation and peace.
According to some Buddhist teachings, believing in rebirth is essential to live an ethical life. Otherwise, if there is no fear of karmic consequences in future, what keeps people from doing wrong things and getting into debts? This argument is sad and invalid, because it states that fear of a punishment is the only thing that prevents us from the evil.