Please do not take seriously the following arguments, but I will try my best to convince you. Earth was believed to be flat for a very long time. Way longer than the current believe of an almost spherical shape. All this time, so many people couldn't possibly be wrong. All current gods (from every religion) people believe in, were created in a time all people believed the earth was flat. Therefore, the gods must have the same belief too. And who are we to question them? As Occam's razor says, the simplest explanation is usually the correct one and that earth is flat is surely the simplest explanation.