When Locke was a child and was asked which belongs to him already...and chose the knife and failed. I have a theory as to what the man was looking for (don't remember his name).

Anyway, he was looking to see if Locke was a reincarnation of someone...and that's the reason why Locke would know about "what was his already". Maybe they thought he was reincarnation of Jacob?

Leads me to think...is that why they wanted Walt??

Or perhaps this fits in with the 'this is a circle/cycle' theories... As in, Locke chooses the knife, and grows up to become the same John Locke we see in the show and, going with those theories, has always been. Kinda like how Neo in the Matrix had to make that choice that all the past Neos had to make. Alpert was hoping that John would choose another thing, something that might indicate a change in the circle

but he didn't. Other than that, I'm not sure, I mean we all seemed to expect him to choose the knife, bc we all know the Locke we see in the show. Wonder what else he could haev chosen (though when i saw that vial, i thought that was a vial of the ash around Jacob's cabin).

My guess is that Locke could be a reincarnation of Adam (http://www.lostpedia.com/wiki/Adam_and_Eve). Locke was born around the time that Jack estimates Adam died. The only question is who is Eve? Oddly enough, the one woman born around the right period is Rose (http://www.lostpedia.com/wiki/Rose).