The bottom line difference-which we all agree on- is that the Law cannot justify anyone-only God can justify us-make us* just*. r heaven-to be even capable of seeing Him-becoming actually just, rather than merely imputedly just. By abiding in the Spirit Who indwells us, man is transformed into the image of Christ-and this involves our* cooperation*. But in either belief, salvation is impossible without God.
More excerpts:
From Justification by Faith by W. Marshner
Stages of Justification
Catholic and Protestant views on the respective roles of grace, faith and works cannot be compared meaningfully, unless one specifies what stage of the justificational process one is talking about. In the preparatory stage, for instance, in which prevenient graces first stir a person towards an interest in religious truth, towards repentance, and towards faith, Catholics, Lutherans and Calvinists are at one in saying "sola gratia."2
A second stage is the very transition from death to life, which is the first stage of justification proper. Here the parties are at one in saying “sola fide,” though they seem to mean different things by it. Protestants tend to mean that, at this stage, by the grace of God, man’s act of faith is the sole act required of him; Catholics mean that faith is the beginning, foundation and root of all justification, since only faith makes possible the acts of hope and charity (i.e. love-for-God) which are also required.3 However, since most Protestants have a broad notion of the act of faith, whereby it includes elements of hope and love, it is often hard to tell how far the difference on this point is real and how far it is a matter of words.
Finally, however, there comes a third stage, that of actual Christian life, with its problems of growth and perseverance. The man justified by faith is called to “walk” with God, to progress in holiness. It is at this stage that the parties sharply diverge. Catholics affirm, and Protestants strenuously deny, that the born-again Christian’s good works merit for him the increase of grace and of the Christian virtues. As a result, Protestant piety has no obvious place for the self-sacrifices, fasts, and states of perfection which are prominent features of Catholic piety.
Grace
What Catholics call “sanctifying grace” or “habitual grace” turns out to be a deeply mysterious entity: a quality of man which is a property of God. In order to cope with such an entity, one needs a sophisticated metaphysics of participation. The Church Fathers and their successors, the Scholastic Doctors, took the trouble to work out such a metaphysics because the existence of grace as a real entity in man—ontic grace—was and is the foundation, without which the whole Catholic understanding of justification makes no sense.
The Protestant Reformers, however, impatient with metaphysics, preferred not to cope with such an entity and denied its existence.4 To them it seemed simpler to say that grace is something wholly in God, namely, His favor towards us. But then, if grace is not something real in man, our “justification” can no longer be conceived as a real change in us; it will have to become a sheer declaration on God’s part, e.g. a declaration that, thanks to the work of Christ, He will henceforth consider us as just, even though we remain inwardly the sinners we always were. Hence, the Protestant doctrine of “forensic” or “extrinsic” justification.
Now watch what happens to our own act of faith: it ceases to be the foundational act of an interior renewal and becomes a mere requirement, devoid of any salvific power in its own right, which God arbitrarily sets as the condition on which He will declare us just. Whereupon, watch what happens to our good works: they cease to be the vital acts wherein an ontologically real “new life” consists and manifests itself; they become mere human responses to divine mercy—nice, but totally irrelevant to our justification—or else they become zombie-like motions produced in us by irresistible divine impulses, whereby God exhibits His glory in His elect.
The Obedience of Faith
For as St. Paul himself says, in a verse which ought to have stopped the mouth of Luther forever, “We are God’s handiwork, having been created in Christ Jesus to do good works, which God prepared beforehand that we should walk in them” (Eph. 2:10). Our new creaturehood in Christ Jesus is our reception, through grace, of the “obedience of faith.” Through that faith, as through an instrument, God has refashioned us, making us now prompt to obey.
Our new estate is thus ordered to good works as to its intrinsic and God-intended finality. With what joy, therefore, do we
walk in them, we who believe! And woe to us if we do not walk in them, for then we betray our faith and frustrate God’s handiwork.
So we have, and are intended to have, works. Does it follow that we may boast? Not at all! For our works, unlike the works attempted by the Jew under the Law, are not from us but from God. Rooted in God’s gift, brought forth by living faith, God’s instrument in us, these works are grace-works. They are our justice through faith, and therefore they are justice in the order of grace (kata charin), not in the order of self-achievement where boasting arises.
Living faith: our quality but God’s instrument; good works: our deeds but God’s handiwork; our deeds as men living in Christ, not the motions of “graced” zombies still dead in sin—these are the possibilities overlooked by Luther and Calvin but preached by Paul and defined by Trent.