The Protestant Doctrine on Justification
according to the Catholic New Advent Encyclopedia

What then is the part assigned to faith in justification? According to Luther (and Calvin also), the faith that justifies is not, as the Catholic Church teaches, a firm belief in God's revealed truths and promises (fides theoretica, dogmatica), but is the infallible conviction (fides fiducialis, fiducia) that God for the sake of Christ will no longer impute to us our sins, but will consider and treat us, as if we were really just and holy, although in our inner selves we remain the same sinners as before. Cf. Solid. Declar. III, sec. 15: "Through the obedience of Christ by faith the just are so declared and reputed, although by reason of their corrupt nature they still are and remain, sinners as long as they bear this mortal body." This so-called "fiduciary faith" is not a religious-moral preparation of the soul for sanctifying grace, nor a free act of cooperation on the part of the sinner; it is merely a means or spiritual instrument (instrumentum, organon leptikon) granted by God to assist the sinner in laying hold of the righteousness of God, thereby to cover his sins in a purely external manner as with a mantle. For this reason the Lutheran formularies of belief lay great stress on the doctrine that our entire righteousness does not intrinsically belong to us, but is something altogether exterior. Cf. Solid. Declar., sec. 48: "It is settled beyond question that our justice is to be sought wholly outside of ourselves and that it consists entirely in our Lord Jesus Christ." The contrast between Protestant and Catholic doctrine here becomes very striking. For according to the teaching of the Catholic Church the righteousness and sanctity which justification confers, although given to us by God as efficient cause (causa efficiens) and merited by Christ as meritorious cause (causa meritoria), become an interior sanctifying quality or formal cause (causa formalis) in the soul itself, which it makes truly just and holy in the sight of God. In the Protestant system, however, remission of sin is no real forgiveness, no blotting out of guilt. Sin is merely cloaked and concealed by the imputed merits of Christ; God no longer imputes it, whilst in reality it continues under cover its miserable existence till the hour of death. Thus there exist in man side by side two hostile brothers as it were — the one just and the other unjust; the one a saint, the other a sinner; the one a child of God, the other a slave of Satan — and this without any prospect of a conciliation between the two. For, God by His merely judicial absolution from sin does not take away sin itself, but spreads over it as an outward mantle His own righteousness. The Lutheran (and Calvinistic) doctrine on justification reaches its climax in the assertion that "fiduciary faith", as described above, is the only requisite for justification (sola fides justificat). As long as the sinner with the "arm of faith" firmly clings to Christ, he is and will ever remain regenerated, pleasing to God, the child of God and heir to heaven. Faith, which alone can justify, is also the only requisite and means of obtaining salvation. Neither repentance nor penance, neither love of God nor good works, nor any other virtue is required, though in the just they may either attend or follow as a result of justification. (Cf. Solid. Declar, sec. 23: "Indeed, neither contrition nor love nor any other virtue, but faith alone is the means by which we can reach forth and obtain the grace of God, the merit of Christ and the remission of sin.") It is well known that Luther in his German translation of the Bible falsified Romans 3:28, by interpolating the word "alone" (by faith alone), and to his critics gave the famous answer: "Dr. Martin Luther wants it that way, and says, 'Papist and ass are the same thing: sic volo, sic jubeo, sit pro ratione voluntas'."

Since neither charity nor good works contribute anything towards justification — inasmuch as faith alone justifies — their absence subsequently cannot deprive the just man of anything whatever. There is only one thing that might possibly divest him of justification, namely, the loss of fiduciary faith or of faith in general. From this point of view we get a psychological explanation of numerous objectionable passages in Luther's writings, against which even Protestant with deep moral sense, such as Hugo Grotius and George Bull, earnestly protested. Thus we find in one of Luther's letters, written to Melancthon in 1521, the following sentence: "Be a sinner and sin boldly, but believe and rejoice in Christ more strongly, who triumphed over sin, death, and the world; as long as we live here, we must sin." Could anyone do more to degrade St. Paul's concept of justification than Luther did in the following blasphemy: "If adultery could be committed in faith, it would not be a sin"? (Cf. Möhler, "Symbolik", sec. 16). The doctrine of justification by faith alone was considered by Luther and his followers as an incontrovertible dogma, as the foundation rock of the Reformation, as an "article by which the Church must stand or fall" (articulus stantis et cadentis ecclesia), and which of itself would have been a sufficient cause for beginning the Reformation, as the Smalkaldic Articles emphatically declare. Thus we need not wonder when later on we see Lutheran theologians declaring that the Sola-Fides doctrine, as the principium materiale of Protestantism, deserves to be placed side by side with the doctrine of Sola-Scriptura ("Bible alone", with the exclusion of Tradition) as its principium formale — two maxims in which the contrast between Protestant and Catholic teaching reaches its highest point. Since, however, neither maxim can be found in the Bible, every Catholic is forced to conclude that Protestantism from its very beginning and foundation is based on self-deception. We assert this of Protestantism in general; for the doctrine of justification as defended by the reformed Churches differs only in non-essentials from Lutheranism. The most important of these differences is to be found in Calvin's system, which taught that only such as are predestined infallibly to eternal salvation obtain justification, whilst in those not predestined God produces a mere appearance of faith and righteousness, and this in order to punish them the more severely in hell (Cf. Möhler, "Symbolik", sec.12).