From the FAQ
2.5 Why can’t I submit a religious or spiritual claim?
Because they are, for the most part, untestable. For example, you can look at a series of events – say surviving an automobile crash, surviving a plane crash, surviving a near-drowning and say “This was the hand of God,” but the point of the Challenge isn’t to give anecdotal evidence. It is to give something testable. Most religious people believe it’s impossible to test God. We’re pretty sure they’re right, though perhaps for different reasons.