A Simple Test Showing Atheism Is the Only Honest Answer

Along these same lines, what if you have different people who think their god has told them to kill the other person (or people of different religions)? If there is a god, how do you objectively say who is right? How can anyone religious, not be biased towards their own religion in this example?

Also, how can you discriminate between someone insane or psychotic -- and someone who says they have been told by god to kill other people?

Ultimately, how is belief in god at all tenable?