I am a Protestant but I struggle with the faith/works paradox that you are talking about. Let’s say I’m a prostitute who comes to a belief in Jesus as my Lord and Savior. If I am saved solely by faith and profess devotion to Christ, yet still work as a prostitute, am I really saved? A Protestant will say that if your life is characterized by sin, then you aren’t really a Christian. But if I’m saved by faith alone and we’re all sinners and all sin is the same, you can’t very well question my faith without impugning your own.
Does God overlook our sins? Is that what saving grace accomplishes for us? Do Protestants believe this? Luther made the analogy that we are like lumps of dung covered with snow. The snow is bright and beautiful and it covers the filth. Our sinful souls are covered by Christ’s blood, cloaked, so to speak, and God sees that instead of our sins and we walk into heaven (in costume?). This bolstered sola fide. In this view and his horse and rider analogy repentance is not necessary. The prostitute keeps her night job. No problem.
Everyone in Christ is a new creature, really new. This means grace does not cover us, but it transforms us, making us truly new, holy, remade, not simply given a fresh paint job. We are sanctified by being transformed in and by grace. If we look into our souls and see sinfulness, real evil, and not repentance and think we are saved we fool ourselves. There are two classes of people, penitent sinners and impenitent sinners. You can call Jesus lord, lord, but if you do not obey (love) Him what good is He to you. If we know we are sinful, in the state of sin, we need the means (grace) of conversion, not simply believing Jesus is who He claimed to be. If we do see personal unrepented sinfulness in our souls and we call out to God presistently He will hear us and have mercy. In His mercy He provides the means to live a grace filled life. The ordinary means of grace are the sacraments.
So what responsibility do I have in any of it? All help is appreciated in my dilemma here.
The responsibility we have, is to avail ourselves to the means God provides.