Jacob's Cabin by Silaqui

OK - just something I have been thinking about.

Most theories/assumptions have taken the cabin to have been an imprisonment to keep MIB inside (hence the ring of ash). I was pretty paid up to this, until I thought of something else.

At one point we saw Claire and Christian in the cabin. What if, in this particular case, Jacob was posing as Christian in order to bring Claire to the cabin? In this case he was trying to protect her - Claire has been able to give birth on the island and so she is special - perhaps this is the 'progress' that Jacob mentions. He knew that MIB would try to thwart this progress and so he wanted to keep Claire safe - manifesting as her father was a way of getting her to trust him.
Once she was inside the ring of ash, this would stop MIB from getting to her.

Obviously this doesn't explain anything else, or the violence that Locke encountered the first time which seems unjacob-like.

But hey it's a thought!