There is a hierarchy of the Revealed Word with the Gospels comprised of the actual words and deeds of Christ at the pinnacle. Everything in the entire Bible must be interpreted in the context of the Gospels. Paul did not come to teach a new Gospel, but to help explain and spread THE Gospel. If you cannot support your interpretation from the Gospel your interpretation is wrong.
In faith, the human intellect and will cooperates with divine grace. As stated by St. Thomas Aquinas: "Believing is an act of the intellect assenting to the divine truth by command of the will moved by God through grace." Grace, freely accepted by human intellect, is what differentiates Mary from a rape victim.
This is not to be confused with the obedience of faith. Remember that to obey (from the Latin ob-audire, to "hear or listen to") in faith is to submit freely to the word that has been heard, because its truth is guaranteed by God, who is Truth itself.
I believe in both free will and predestination and don’t think they have to be mutually exclusive. I know others will reject that notion.
God is the one, who according to His mercy, draws people to Himself and opens their heart so they are receptive to the Gospel. Obviously, God knows who will accept the Gospel and so I believe He opens their heart so they are able to do so. But, I still believe it is incumbent upon each person to believe on their own accord.