I don't get it, and I'm a devout evangelical, if I do say so, myself. I was looking for the pun in the guy's name, and didn't find it.

"Our God is awesome"? Not only is this entirely grammatically correct, or within the typical Christian use, but likely influenced by the lyrics of the song "Awesome God" by Rich Mullins, which is quite popular among evangelicals. The flame does not represent hell, but the fire of faith, or the Holy Spirit. Terrible graphic design is par for the course in Christianity, today, sad to say.

And, as for the blank below the name, I've seen far more ironic things written on church signs, often accidentally.

And it includes Pluto as a planet! I like!