Okay…let’s talk about the mysteries of this show that are slowly revealed and the mysteries that continue to appear.
This season will help us find out the truth about the island and the purpose of those who ended up there.
The most important figure in this season [til now] is John Locke. This character was from the beginning described as a believer, a man with faith, who refused to leave the only place where he felt like home…the island. He was the first to encounter the smoke monster.
And from that scene we evolved to Locke as being a substitute and an important “candidate”, whatever that is.
This episode right here learns us that The Kwon couple or just one of them , Hugo , Locke , Jack , Sayid  and James  were candidates to protect the island. This is Jacob’s doing.
The new Locke/Man in Black/Smoke monster told Sawyer that this kind of “candidate” can do three things: to protect the island like Jacob did, to do nothing or to go home.
From his tone protecting the island was like something irrelevant, just a waste of time…but if you look deeper into this show you’ll see that protecting the island really means something. If that wasn’t nothing to protect then the island would be invisible for the outside world and the island couldn’t be moved.
So we just found out some facts while other are still blocking our way to the truth.