I was just thinking....and please forgive me, putting my thoughts to written word is not one of my strong points.... but here goes.
OK. Thinking about the scene inside Jacobs foothouse where Ben walks in and finds an upset Ilana. She asks what happened to her friends and Ben informs her that a pillar of black smoke killed them. She then asks if the smoke killed Jacob and Ben lied and said yes. So anyway, i would think that Ilana being a servant/protector or whatever of Jacob, wouldnt she know that MIB/smokemonster wasnt allowed to kill Jacob? Is this why she says that MIB will be stuck in John Locke's body? Also, I forget at what point, but we see FLocke have a flashback of pushing Jacob into the fire....this flashback must be signifigant, right? Maybe MIB broke the rules because pushing Jacob in the fire is what actually caused his death. Any thoughts?