One of the big questions from last season on the show Lost was "what lies in the shadow of the statue?" To which Richard Alpert replied, "Ille qui nos omnis servabit" ("He who will save/protect us all"). Latin's the secret language of the Others, and being able to answer that question demonstrates a knowing fidelity to Jacob, the island's god-like seeming protector/ruler/primary servant. Those with the answer have been (it seems) in personal contact with Jacob, rather than merely receiving his orders through some tertiary representative. Complicating the exegesis here was the appearance last season of another figure in the statue's shadow, Jacob's nemesis (as yet unnamed, but many have suggested Esau for good reason -- which is only reinforced in Season 6's premiere when he, in the form of Locke, states his rasion d'etre is to go home, or, one might say, reclaim his birthright -- "home" would appear to be the Temple, where he once resided as the smoke monster, but is now kept out using that protective ash). At the beginning of Season 5's finale, while watching the arrival of the Blackrock (an old pirate ship), there was a God versus Satan sort of dialog between Jacob and his nemesis, expressing their respective positions towards man (qua island visitors):
Nemesis: They come, they fight, they destroy, they corrupt. It always ends the same.
Jacob: It only ends once. Anything that happens before that ... is just progress.
A straightforward reading would be the tried and true and utterly boring good versus evil, but Lost never does anything straightforwardly, so I ain't buying it. First, notice the pun on 'lies' in the question: both Jacob and the Nemesis are shown existing by the statue, but, like that old riddle of the doors (cf. Labyrinth), we viewers don't know which one might be lying, leading to damnation, or telling the truth, leading to salvation (or if they're both liars). The Nemesis has certainly been a deceiver, but it might prove in the service of truth (e.g., the classic case of hiding Jews from Nazis). The clearest case of his deception is in taking the form of Ben Linus' dead daughter, Alex, in order to get Ben (who's a master of deception in his own right) to follow the Nemesis' other avatar, Locke, in his plan to kill Jacob (and thereby giving the reason why Ben wasn't supposed to return to the island after leaving it at the end of Season 3). Which brings up the second problem: who's plan necessitated the death of Locke and the return of the Oceanic 6 to the island?
The apparition of Jack's father, Christian, informed Locke that he'd have to die (as a "sacrifice") in order to bring the 6 back (there was a time loop involving Richard Alpert, but basically it was Christian). Now, it's questionable whom this apparition is serving, but it seems clear enough in Season 5's finale that Jacob was the one taking an interest in having the 6 come together on the island in the first place (he's shown visiting each of them at a point in their lives). Furthermore, he gives Hurley a guitar case whose content -- a big ankh with a message inside -- plays a crucial role in Season 6's premiere, namely in getting his Temple followers to repair Sayid (who's shown dying and then resurrected at the end of the episode). Thus, the loophole that the Nemesis needed to kill Jacob came about through the latter's own machinations, namely the former begins to use Locke's form only after he's died due to Jacob's devising. Being fully aware of the rules of the game he's playing, it is to counter the Nemesis' likely (preordained?) move (i.e., the taking of Locke's form) that Jacob requires the real Locke's body to be returned to the island (as material counterevidence to this guy who looks and sounds like Locke). My point is that both of these island entities practice deception to get their "game pieces" into place (Jacob, for example, withholds foreknowledge of Sayid's death to get Jack and his team to the temple), and we viewers have no reason for suspecting one is more benevolent than the other. So what about Sayid?
It would seem that the resurrected Sayid is being set up as a new body for Jacob to go against "UnLocke," pointing to some simplistic Manichaean battle on the horizon. And, sure, we see Sayid in a variety of crucified Christ poses leading to his being baptized in the Temple's fountain. But the Last Supper promo poster (shown at the top of this post) suggests a third ambiguity. UnLocke is in the position of Jesus, Sayid as Judas. And, as I discussed previously, Lost has so undermined the use of faith as a crutch (cf. the Nemesis' take on Locke's dying thought: "'I don't understand.' -- Isn't that just the saddest thing you ever heard?") that even if the narrative comes down to two opposing forces, the decision to side with one over the other will in and of itself be unlikely rewarded with some Divine assurance, gratitude or redemption. Note the common element of determinism in both of the theistic players' interpretation of their game: Jacob's version is that of teleological progress to one point, a straight line being drawn through possible worlds. The Nemesis' view is that of the eternal return, the same players and events going round and round. (The alternate universe that's now been set up could support either view.) Locke's faith reduced him to a point on the line, or cog in the wheel. As UnLocke suggests of his source material, there's something admirable about Locke's fidelity to this newfound order and his rejection of the "pitiful life he left behind," but, then again, Jack's assertion of his own agency, his existential resistance to the deterministic order by attempting to nuke it out of existence, has left him alive.