I have this sort of half-assed theory that no one really "sells their soul" to the Devil. Rather, the Devil just convinces you that you no longer have possession of it.

Like, I wouldn't need to shove a gun in your face and carjack you if I just came to your door wearing a plastic badge and shoved a bunch of paperwork in your face along with a lot of fast talk about fees and levies, failure to file, impoundment, registration, federal and state, vehicular forfeiture, .... Maybe you just hand over your keys and I drive off in your ride.

Point is, just don't let anyone talk you out of your soul and try to spread the word to any who will listen. Actually, I think Jesus pretty much said the same thing.