"This is just a thought I'm giving attention to... Imagine that Christian is in opposition to Jacob (or smokey, or whoever appeared to Locke as Walt). Christian says Jack 'has work to do' as in getting everyone off the island, even at the cost of his happiness. Jacob(or smokey) tells Locke that he has work to do, as in keep everyone on the island. This puts Christian and Jack in direct oppostion to Jacob (or smokey) and Locke. This follows right in line with the duality of the show (such as Locke's description of backgammon... "two sides, one light, one dark" "

That is what someone wrote on another site,DARKUFO's site,which is awesome. Anyway,word for word,totally agree with that. It makes sense.It also adds to the many many differences between Jack and Locke. Both are good,in different way. One a man of faith,one a man of science. One wants to leave the island, the other wants to stay. One is right, the other is wrong. It's a great theory folks. Thanks for that dude!