I stated in my comment in the thread "Colleeen's Funeral" that there may be a connection between Merlin an dthe Smoke Monster. I stated that the show may be the conflict between paganism and Christianity. I just have been thinking about smoke in its connection to Christianity. White smoke is always a positive; black smoke is always a negative. Consider: white smoke of incense, white smoke in the election of the Pope, etc.; Black smoke of Hell.

Locke faced down the Smoke Monster and survived. To this point, we have no evidence that Locke has committed an act that requires contrition. However, Ecko had committed many such acts. When confronted with them, he refused to confess as required by revealed religion (Christianity). Instead he defended himself by relying on the precepts of natural religion: I had no choice, I did the best I could.

He did not talk to the apparition as to a priest (a man representative of revealed religion) but as to Yemi (a man with natural connections, a human brother). Therefore, the Smoke Monster executed judgement upon Ecko.

His dying words show Ecko's final understanding. Everyone must make this ultimate decision: You're next.