I think one of the biggest reasons why Protestants disagree with Catholics on the issue of justification is because Protestants misunderstand what Paul means when he says the Law does not save.
Three passages come to mind:Rom 3: 28For we maintain that a man is justified by faith apart from observing the law.
Gal 2: 16know that a man is not justified by observing the law, but by faith in Jesus Christ. So we, too, have put our faith in Christ Jesus that we may be justified by faith in Christ and not by observing the law, because by observing the law no one will be justified.
Gal 2: 21I do not set aside the grace of God, for if righteousness could be gained through the law, Christ died for nothing!When Protestants read these passages they think it is saying we are NOT justified by the law because the law demands perfection and we cannot keep the law perfectly.
Now, look at how a popular Protestant Apologetics page defines justification:Justification is the work of God where the righteousness of Jesus is reckoned to the sinner so the sinner is declared by God as being righteous under the Law.
(Christian Apologetics and Research Ministry)
What this is saying is that since the law demands perfection, and we cannot keep it, Christ had to keep it for us so that we could be justified (considered to have kept the Law perfectly).
Protestants often point to Gal 2:21 (above) and say Catholics trying to be justified not by faith alone makes a mockery of Christ’s sacrifice and tramples upon Christ making Him no value.
BUT all of this is a misreading of what St Paul is saying.
WATCH CLOSELY, Paul is NOT saying justification is by faith because we cannot keep the law perfectly, he IS saying the law itself lacks the power to save, and that is why justification is apart from the law.
Gal 2: 21 is saying that IF the law could save then there really was no need for Christ, salvation would simply be based on those who followed the law. It is NOT saying: you can EITHER choose to try to be justified by keeping the law on your own OR trust that Christ kept it for you.
St Paul is saying simply that the Law does not save because it not only lacks the power to, it was NEVER INTENDED to save.
Imagine us sinners were represented by dead batteries, while the Mosaic Law represents a battery powered toy car. The toy car CANNOT give life to that battery, it cannot charge the battery, thus charging the battery must come APART FROM the toy car. The toy car LACKS the power to charge the battery, infact it was NEVER INTENDED to charge the battery.
Jesus is the battery charger, by His own power He can charge whatever batteries come to Him.
Now, as charged batteries we can make the toy car work the way God originally wanted to see the toy car in operation, in that sense we are called to and must fulfill the law.Rom 13: 8Let no debt remain outstanding, except the continuing debt to love one another, for he who loves his fellowman has fulfilled the law. 9The commandments, “Do not commit adultery,” “Do not murder,” “Do not steal,” “Do not covet,” and whatever other commandment there may be, are summed up in this one rule: “Love your neighbor as yourself.” 10Love does no harm to its neighbor. Therefore love is the fulfillment of the law.
This was the reading everyone at Mass heard on Sunday for the Epistle Reading. Jesus gave us the power to love on the supernatural level, the love that pleases God, something we could not do when stripped of sanctifying grace because of Adam’s sin.
For those Protestants who are not convinced what I am saying is true, take one final passage, which I think lays out the problem very clearly:2 Cor 3: 3You show that you are a letter from Christ, the result of our ministry, written not with ink but with the Spirit of the living God, not on tablets of stone but on tablets of human hearts. 4Such confidence as this is ours through Christ before God. 5Not that we are competent in ourselves to claim anything for ourselves, but our competence comes from God. 6He has made us competent as ministers of a new covenant—not of the letter but of the Spirit; for the letter kills, but the Spirit gives life. 7Now if the ministry that brought death, which was engraved in letters on stone, came with glory, so that the Israelites could not look steadily at the face of Moses because of its glory, fading though it was, 8will not the ministry of the Spirit be even more glorious? 9If the ministry that condemns men is glorious, how much more glorious is the ministry that brings righteousness!
Justification was not, as Luther and Protestants mistakenly thought, a matter of being found righteous by the law. Instead, justification according to St Paul is a resurrection of our spiritually dead souls, given life not by the Law (which lacked the power to give life) but by the epitome of life itself: The Holy Ghost, indwelling.
THIS is the real dispute between Protestants and Catholics, it is NOT a matter of “faith” versus “faith plus works.” It is about what justification means IN LIGHT OF WHY the Law CANNOT save.