Lost!

[sleepyjeff]

Originally Posted by bewitched

There are 2 different motivations at work. I think MIB's mother didn't want him to leave because A. she wasn't sure, until MIB killed her, which of the 2 brothers would be the new guardian of the island and B. she wanted her "sons" to remain "uncorrupted" by outside influences.

Jacob, on the other hand won't allow MIB to leave because he now holds too much of the light and, if the light is allowed to leave, "it will go out in all of us."

Makes sense.