Christianity
In most superhero flicks, it's not too difficult to draw a parallel between the main character and Jesus Christ. But most superhero flicks don't have their big bad hanging out in burning buildings and threateningly quoting the Bible, though.
There are several Christian symbols and references in Spider-Man. For starters, Peter is Christ-like in his willingness to sacrifice his happiness (and his life, if need be) to save the lives of others.
Sounds like a certain Jewish carpenter we know, right?
Most of the Christian imagery in Spider-Man is associated with the Green Goblin and his depiction of the Christian concept of evil, though. First of all, there's his mask, which makes him look like a green version of pop culture's depiction of the devil.
Second, there's his love of hanging out in fiery hellscapes. One of Green Goblin's biggest battles with Spider-Man takes place inside a burning building that the Green Goblin tricks Spider-Man into entering. As the flames flicker menacingly in the background, it's hard not to see the allusions to the underworld in the Green Goblin's preferred battle locale.
When the Green Goblin attacks Aunt May, he does so while she's kneeling beside her bed saying the Lord's Prayer. Check out how it all goes down:
AUNT MAY: Lead us not into temptation, but deliver us—
The Green Goblin blows up Aunt May's bedroom wall. She falls to the floor, screaming.
AUNT MAY: Deliver us!
GREEN GOBLIN: Finish it! Finish it!
AUNT MAY: From evil!
The Green Goblin sure seems to delight in being evil, doesn't he? If we wanted to nitpick, we'd make the argument that harassing pajama-clad senior citizens isn't the most brazen of supervillain moves, but the next time the Green Goblin gets all biblical, he's got Mary Jane and a tramway car full of kids held hostage on the Queensboro Bridge.
Consider that ante upped, we guess.
When Spider-Man arrives at the bridge, the Green Goblin presents him with an ultimatum:
GREEN GOBLIN: This is why only fools are heroes. Because you never know when some lunatic will come along with a sadistic choice: let die the woman you love or suffer the little children.
That last part is a quote from the Bible, specifically Matthew 19:14, which says:
But Jesus said, Suffer little children, and forbid them not, to come unto me: for of such is the kingdom of heaven. (Source)
"Suffer" in this verse actually means "allow" or "permit." The line comes from a story where a bunch of kids want to see Jesus, and his friends, assuming he doesn't want to be harassed by a pack of rugrats, try to shoo them away. Jesus is saying, "No, no. That's cool if those kids want to come see me."
Knowing that, if we take another look at what the Green Goblin is saying to Peter, he's quoting scripture to say, "You've got two options: allow M.J. to die, or allow the little children to die." The fact that the line from Matthew uses the word "suffer" only makes the choices he's presenting sound more sinister.