Can you elaborate on some of the errors of Luther’s beliefs?
I'll focus on a central one, Sola Fide. Protestants often make the claim that Catholics think they must earn their way into heaven, taking some of the credit for our salvation away from Christ and placing it on ourselves. There’s a germ of truth in this in that we believe we must participate in working out our salvation, cooperating with grace, at God's discretion and according to His wisdom.. The Protestant position is that our only obligation is to believe. The difference is sometimes referred to as synergism vs monergism but even most Protestants, regardless of theology, generally simply know that what they
do, how they comport themselves throughout their lives, and not only what they believe, matters as to their eternal destinies. But theologically some believe that faith can be distinguished between a “saving/true faith” and a "dead faith", and that a true faith will
automatically lead to a righteous life but that such righteousness will nonetheless still not save them; only Christ’s sacrifice and
His righteousness does that. As long as we trust in Him and His work, trust that we’re forgiven because of it, they say that we’re saved, as His righteousness is now imputed to us.
This leads to a bit of confusion already though, because it places a disconnect or point of confusion between whether or not we can and need to possess any personal righteousness, whether or not sin can still possibly separate us from God. Is man still
obligated to be righteous under the New Covenant or not? Scripture says yes. Luther said that we’re “
simul justus et peccator”: righteous and sinner all at the same time. We’re simply
declared to be righteous by God, rather than being
made righteous. This “declared righteousness” concept also calls into question whether or not one can
lose their salvation; if righteousness is said to be declared or imputed
only then what’s to lose? In Catholicism we can compromise and lose our state of justice by living and acting
unjustly.
So, to sum it up, Lutheranism teaches that we’re justified by the sheer act of faith/trust whereupon God forgives sin and declares us just, while in Catholicism faith is the
vehicle to real justice/righteousness
given to us as it’s the vehicle to
God, to union with the only One who can accomplish the righteousness in us, by grace, that we cannot accomplish on our own, under the law. We’re saved
by faith, through and on the basis of faith, “not having a righteousness of my own that comes from the law, but that which is through faith in Christ—the righteousness that comes from God on the basis of faith” (Phil 3:9).
It’s all a matter of who we fellowship- or commune- with; God, alone, can justify man. Adam had thought he was perfectly fine-or better yet- without Him. But, “Apart from Me you can do nothing” (John 15:5). All this is consistent with the New Covenant prophecy of Jeremiah 31:33-34:
“I will put my law in their minds
and write it on their hearts.
I will be their God,
and they will be my people.
No longer will they teach their neighbor,
or say to one another, ‘Know the Lord,’
because they will all know me,
from the least of them to the greatest,”
declares the Lord.
“For I will forgive their wickedness
and will remember their sins no more.”
Anyway, the Catholic Church teaches that it’s
all grace, all a gift which He gives and initiates, whether faith or works or any other response we need to make. We cannot possibly turn ourselves to and follow God; He must reach down and touch and move us first. But we can still always refuse to come, to open the door, or to keep it open throughout our lives. We must accept, embrace and express the gifts given-and to the extent that we do so we grow in them: our justice/holiness is increased. Once freely justified we’re now empowered, by the Spirit, by grace, by love, to begin to love as He does with all that is entailed in that. We can also turn and walk away from it, from Him, at any point in time, returning to the flesh. At any rate the Church teaches, “At the evening of life we shall be judged on our love.”
That’s the real thing. Faith is not a replacement for righteousness or the equivalent of it, nor is it a get out of hell free card but rather it's finally the means to authentic righteousness by becoming children of God, like Him, loving as He does, which makes us truly worthy of heaven. It’s a two-way effort: God
wants our participation, and increasingly so, for our own highest good. He loves man lavishly. Faith puts us on a
journey, with and to God. We must remain on board-not with sinless perfection in this life, but certainly oriented with Him towards righteousness, growing more towards the purpose and perfection He designed us for than towards sin and the flesh, away from Him.
“Therefore, brothers and sisters, we have an obligation—but it is not to the flesh, to live according to it. For if you live according to the flesh, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live.” Rom 8:12-13
Sorry if I elaborated a bit too much there
.