[TheBeard]

I also had a thought strike me last night:

From what we've been shown of the Temple previously (that is to say, the area underneath the outer walls that surround the Temple), we've been lead to believe that the Temple is either where the smoke monster lives or is under the protection of the smoke monster, or something along those lines. Yet when the Others inside the Temple found out about Jacob's death, they immediately went into "lockdown mode" and made a point to draw a barrier of ash about their Temple's inner walls.

We saw the same ring of ash encircling Jacob's cabin, and every time we saw this ash we were also shown a gap in the ash. Ilana and her crew pointed out that this meant that Jacob had not been in that cabin for some time (which, now makes me wonder if it's been the smoke monster who's been leading everyone on the island along, especially Locke, with visions of dead people). The reason for this ash was shown to us when the smoke monster attacked Brahm and the others: Apparently, Smokey can't cross that barrier.

Now, my question: If Smokey had been so near the Temple for so long, why wasn't there an ashen barrier in place to begin with? What was keeping him out of the Temple? What power does (did) Jacob have to keep Smokey at bay? If Jacob's cabin needed to be protected by ash, was his room "in the shadow of the statue" any different?