Not sure if anyone has mentioned this, thus apologies if it has been raised before
Do we think this line by the MiB is (a) merely a lie to Ricardo to try and convince him Jacob is evil and thus needed killing in order for him to see Isabella again or (b) of greater significance?
When I first watched Ab Aeterno I found this quite interesting, in that what if Jacob's body as we know (the man in white) is infact the body of his nemesis (he has taken it somehow). Of course then, I would need to explain whose body is Titus Welliver's which leads me down a lonely dark path of nonsense. If you do find this nonsense or simply one of MiB's lie's then it needs no further analysis. However, if anyone does have any ideas to how it might literally have meaning then please feel free to share.
Reading Lccf's recent MiB and the blonde kid (and his question of whether the kid might actually be the MiB's original self reminded me of that line in Ab Aeterno (although I think him telling himself he cant kill 'him' as it's against the rules would certainly need explaining)