The Council of Trent then explains the Roman understanding of what is the instrumental cause of justification which is, “is the sacrament of baptism, which is the sacrament of faith, without which (faith) no man was ever justified,” another spit in the face of Reformation theology. Biblical theology allows faith alone as the instrument of justification (some Protestants allow that baptism is the instrument of regeneration but not justification). Luther says, “Faith, however, is something that God effects in us. It changes us and we are reborn from God, John 1:13. Faith puts the old Adam to death and makes us quite different men in heart, in mind, and in all our powers; and it is accompanied by the Holy Spirit. O, when it comes to faith, what a living, creative, active, powerful thing it is. It cannot do other than good at all times. It never waits to ask whether there is some good work to do; rather, before the question is raised, it has done the deed, and keeps on doing it. A man not active in this way is a man without faith. He is groping about for faith and searching for good works, but knows neither what faith is nor what good works are. Nevertheless, he keeps on talking nonsense about faith and good works.”
The last point with which biblical theology departs from Tridentine theology is in the relation between the justified and their sin nature. Trent says that a justified sinner is completely free from the stains of original sins, however, Luther states something entirely different. While on earth the sinner is simultaneously sinful and just (simul iustus et peccator). Peter Toon says this, “While on earth, the position of the Christian does not change. He is totally righteous through faith, and he remains always and completely a sinner. With reference to Christ he is righteous; but with reference to his fallen nature he is sinful. Yet this apparent contradiction does not imply a static situation. The very faith that draws Christ into the heart and creates the new nature gladly and freely allows Christ to do battle against the old, sinful nature (= “the flesh”). The result of this spiritual conflict (described by St. Paul in Romans 7, 8) should be that “Christ is constantly formed in us and we are formed according to his own image.”12 Each and every day faith is to grasp anew the word of promise which is the gospel and appropriate Christ, who is our righteousness. Further, each and every day sin, the devil and temptation must be fought. Yet despite all the daily battles, the old nature remains with us until death. There is no escape from it, nor from the possibility of sin. So Luther has no doctrine of progressive holiness or growth in sanctification (as these terms were later used). The flesh or old nature does not change; rather, Christ (or really the new nature) grows within the believer. Justification includes the daily renewal of the new nature. The believer can never say he is less sinful than he was at any earlier time!”
There are some of the areas in which the biblical doctrine of justification cannot be held within the context of the Roman Communion and one of the primary reasons why I am not a Roman Catholic.