While Romans and Galatians are expecially often cited in support of once-saved-always-saved heresy (or whatever its politically correct name is these days), both Romans and Galatians start with correcting the respective errors St. Paul is addressing -- belief is salvific character of works of Jewish law, or works of Roman law, or works for either temporal or spiritual reward -- and then proceeds to exhort his readers to works of charity, and to teach them how to increase their faith. This is in fact true for all his "geographical" letters.
Any good works that I may do is simply because of God working through me. Granted, I can make this easy or difficult on myself, such as Jonah. God will for me will not be stopped just because I decide to go one way than the way God wants me to go. God will bring me around. At what precise point do you think that God will stop reproving you to let your "free will" kick in?
Many people, including my Protestant brethren, seem to think that God gives a command and then moans when we don't follow through. What utter nonsense to talk about our majestic God in such terms.