Religion=Fandoms

Throughout history there are mentions of great people who supposedly lived thousands of years ago, like God who performed miracles for the Masses. He did great things like walk on water and turn water into wine, where are these great men now? How can a huge amount of people believe in these figures who have done nothing to prove they exist for millenia. Are we just supposed to follow with all of our hearts because of things that we hear about in book? Albeit these are some of the best selling books of all time, but how is this any different from following a character from any other best seller like say Harry Potter. Harry Potter did some pretty incredible things like defeat the dark lord, the most evil person in their universe.