Works like this:

|       | Belief       | Non-Belief  |
|------ |--------------|-------------|
| Right |Go To Heaven  | no loss     |
|       |Big Gain      |             |
| Wrong |Small Loss    |10 Die       | 
|       | (some time)  |20 GOTO Hell | 

So, you basically may lose a trifle amount of time in religious services if you're wrong about believing God exists, but you have a lot to gain if you're right, which, if you were a gambling type, it would make more sense to bet on God existing, because that comes with the biggest pay off.

Initally, this was offered as an initial motivation for a person to join the Church, and later it was supported by internal Dogma. This was the First Step, so to speak.