The original proposition was unfortunately painted into a specifically religious landscape. And that throws a lot of people off the logic track. But let's remove that religiosity and try to consider the proposition based solely on the logic track.
The proposition asserts that:
1. God either is, or is not.
A. If God is not, nothing is gained or lost by rejecting God as a possibility.
B. But if God is, then whatever the idea of God might offer us becomes available to us when we choose to trust in that idea.
C. (conclusion) If trusting in the idea that God is offers us nothing, then nothing is lost or gained from our trusting in that idea. However, if trusting in the idea that God is does offer us something, then there is something to be gained from our trusting that God is, and there is something to be lost by our not doing so.
Once we remove the religious jibber-jabber, I think the proposition becomes logically sound.
What do you all think?