This is one of those debates that from the predestination point of view is meaningless. Why? Because God has simply predestined me to believe in free will, so nothing can change that.
The Bible teaches both, free will and predestination. Instead of choosing just one, we must reconcile both.
But you ask: Where is free will taught? For example: When God commands His people to repent, and says "but ye would not" or something similar to that.
It would make no sense for God to ask people to repent, when it is infact His fault they wont repent. All God has to do is give them repentance and faith, as the calvinists believe. Yet God refuses to give people this grace, and continues to ask and command them to repent. This is not logical, nor biblical, and just makes God out to be the same as Pharaoh in these verses:
Exodus 5:16 There is no straw given unto thy servants, and they say to us, Make brick: and, behold, thy servants are beaten; but the fault is in thine own people.
Pharaoh was asking something unreasonable.