Fans have suggested a variety of theories behind the mysteries of "Lost" since the ABC series was launched in 2004 — alien races, secret government plots, shared dreams, purgatory.

Fans have suggested a variety of theories behind the mysteries of "Lost" since the ABC series was launched in 2004 — alien races, secret government plots, shared dreams, purgatory.

The twisted, confusing and complicated mythology of "Lost" meant every frame and phrase had to be closely scrutinized for clues to the baffling meaning.

All of "Lost's" secrets might not be revealed in tonight's finale, but at least enough clues have been revealed this season that fans, experts and even the actors say the show's storylines have been based in spiritual teachings. There is a one-hour recap show at 7 p.m.

The primary message is that no matter what kind of life you have lived — doctor, soldier, scientist, thief — redemption is available to everyone.

The journey to find this salvation, like a modern day version of John Milton's "Paradise Lost," has had the flawed survivors of the crash of Oceanic Flight 815 face challenges from polar bears to atomic bombs as tests.

And now that the end is here, some have seen the light while others remain in the dark.

Chris Seay, a Houston pastor, has written "The Gospel According To 'Lost'," a book that takes an in-depth look at the Biblical references from the show. He suggests it's the seemingly infinite ideas, philosophies, and Biblical metaphors that have made the series popular.

He stresses "Lost" hasn't been an exact representation of the Bible, but more of a post-modern vision of events in Genesis and Exodus.

Seay compares "Lost" to the writings of C.S. Lewis, who adapted Biblical teachings for his "Narnia" stories.

It won't be clear whether "Lost" has gone by the Good Book or created a story that is a mish-mash of spiritual and philosophical ideas until after the finale airs tonight.

The ending could take a 90-degree turn to one of the many other theories about the show. Even if that happens, spiritual teachings have been a big influence.

"For the writers of 'Lost,' the Biblical narrative is a big part of the larger story.

It has come into play more than philosophy, science or other religions — such as Hindu — that pop up. It dominates in a way the other themes have not," Seay says.

Some of the narrative has been as simple as naming characters after those in the Bible, such as Jacob and Aaron. They've also been as complicated as the island being a parallel to the Garden of Eden.

The purgatory theory, says Seay, is off the mark.

He points to Jacob's description of the island as "a cork holding back the evil" as being more in line with the island being the Gates of Hell.

"Lost" has consistently dealt with the battles between having faith and needing a reason to believe, particularly with the characters of Locke (Terry O'Quinn) and Jack (Matthew Fox). Locke told Jack their differing views on faith and reason were why they always disagreed.

Henry Ian Cusick, who plays Desmond, the man in the bunker who loyally entered a series of numbers into a computer every 108 minutes because he was told the world might end if he stopped, says the faith his character showed has been a clue to the show's religious framework from the beginning.

"The religious context for me came up in season two with the pushing of the button. That's a great metaphor for faith, religion. It hasn't just sort of appeared. But it's not so much religion, it's more spiritual. I think it's more of a spiritual show and I think it's going to be very strongly spiritual toward the end," Cusick says.

That numerical sequence — 4, 8, 15, 16, 23, 42 — popped up many times but the religious meaning became clear this season when the Smoke Monster, in the form of Locke, told Sawyer (Josh Holloway) it's the numbers of the "candidates" to take over Jacob's role as the island's "protector."

Jacob's final campfire ceremony to find the protector looked to Seay like an old-fashioned revival.

The job of guardian was available to anyone willing to accept it and ended with a ceremonial drinking of a cup of water similar to the Eucharist, a re-enactment of the Lord's Supper.

The major promotional photograph for this season of "Lost" featured the cast lined up on one side of a long table staged in the same manner of Leonardo da Vinci's painting of The Last Supper.

Some of the "Lost" characters have taken on more Biblical characteristics than others. Nestor Carbonell's Richard was given the gift of eternal life because of his strong faith — the foundation of both Judaism and Christianity.

"I had to report to a higher power and that was always Jacob who was sort of a nebulous higher power so it kind of always felt religious or spiritual in that way," Carbonell says. "When they explained my backstory this year, we definitely got into religious themes about the devil and, obviously, good vs. evil as well as mythological themes as well."

Those themes come to their conclusion tonight.