I think scripture is very clear that those that are unsaved would under no circumstance chose salvation of their own accord without an outside influence acting on them first.
The darkness hates the light, all have sinned, we are all corrupt, every single one of us. It is just not within the natures we are born with to chose God.
So he has to move in us first to enable us to make that choice.
Then you come to the question of does he enable people knowing that they ultimate will not chose him (which makes out God to be quite cruel) or does he enable those he knows will chose him.
The later is pretty plainly explained in scripture... it's called predestination.
God chooses Christians based on is own divine will much like he chose the descendants of Abraham in the Old Testament.
Ultimately it is he that does the choosing, not us.
If you believe that then you also believe that God is unjust.
The Holy Spirit is in the world calling all to come to Christ. Not all come to Christ. Many love their sins more than they love Christ.