In what ways could one make a campaign setting that is a synthesis of Fallout: New Vegas and the Bible's New Testament? Let's say the game's canon can be played a little fast-and-loose, I.E "this is a different timeline, don't expect everything to be like the game."
My friends brought this idea to me, and I can't stop rolling it around in my skull. We play GURPS, if that's important.
Played Honest Hearts?
Truthfully, I only got to play Dead Money and Lonesome Road. But I have an embarrassing amount of playtime through the entirety of the base game.
A lot of people shit on that one but I like it.
Joshua was an absolute treasure.
Well, look into it, christian themes have a prominent place in it, should give you some inspiration.
Also, look into Dogs in the Vineyard.
In a 'sense', Good Karma Courier with Independent Vegas is kind of like what would've happened if the Jews image of Jesus (a.k.a. great jewish warlord who would defeat all of Israels enemies) came to fruition.
In some ways you could frame the Second Battle of Hoover Dam as Revelations...
Ulysses could perhaps serve as a sort of John the Baptist equivalent, who spreads the myth of the Courier as great harbinger of destruction and change.
Of course Honest Hearts could be used as a "Moses and 40 Years Wandering"-esque adventure, wherein it stars Daniel as well.... "Moses" guiding the Sorrows out of Zion into a new Promised Land. I realize that's Old Testament but... fast-and-loose
Some of the DLC locations (Big MT, The Divide, Sierra Madre) are pretty eldritch-esque which to me is somewhat more evocative of Hell. With my loose familiarity with Dante's Inferno, you could use those locations as "Circles of Hell".
The '12 Disciples' could be seen as The Courier's companions, since much like Jesus, he teaches them shit and brings them misadventures.
You could take the Deadlands route of narrative but having things set up as a story being told by a Narrator. Which would explain things away like fast-travel, healing, hammerspace, etc.
A dumb idea which makes nah sense but change the prelude of the story: Courier delivering the Platinum Chip. The Courier having woken up from being shot in the head, starts somewhere else instead of Goodsprings. So he tracks down Benny and finds Benny crucified, he tries to negotiate with some of the Legion but fails and thus uses aggressive negotiations. Which fails.
Gets buried in a shallow grave, but is resurrected by "X" (X = Plot Device/Plot Character).
Read A Canticle for Liebowitz
This man speaks truth. My favorite part is an account of the nuclear war in the style of the bible. Worth reading on its own merits, doubly so for someone interested in religion in the post-apocalypse.
It's a fascinating look at how the mundane can become symbolic or even sacred in the right context.
I think it also does an excellent job at showing that modern religions with millions followers aren't likely to die the wasteland. They'll adapt and become syncretic with local beliefs.
There's an excellent scene in the final chapters of the book about a new type of messiah born without original sin.