I was reading John Bugay's discussion concerning Roman Catholic and Protestant disagreements over justification and sanctification, and this quote from Trent caught my eye and immediately caused me to think of a biblical passage. The Tridentine reasoning is below:
In the case of those who, having been justified, have sinned, the grace
lost is restored, for the merits of Christ, through the sacrament of
penance, which is provided as a second plank to rescue those who by sin
have shipwrecked grace. the penance includes (a) sorrow for sin; (b)
confession of all known sins – at least the desire to do so – to a
priest having jurisdiction; (c) sacerdotal absolution; (d) satisfaction
by alms, fasts, prayers, etc., and finally by purgatorial fires – which
all avail for the avenging and punishing of past sins, as well as for
the discipleship of the new life, and are meritorious satisfactions to
divine justice, canceling the temporal punishments involved in the guilt of the sins for which they are undergone, the eternal
punishment whereof having been freely and at once remitted, either by
the sacrament itself, or by the honest desire for it. (Conc. Trent.,
Sess. 6, chaps. 14 and 16, and can. 30, Sess. 14, chaps 1-9.)
Contrast this with 1 John 1:7-10:
But if we walk in the light as he himself is in the light, we have fellowship with one another and the blood of Jesus his Son cleanses us from all sin. If we say we do not bear the guilt of sin, we are deceiving ourselves and the truth is not in us. But if we confess our sins, he is faithful and righteous, forgiving us our sins and cleansing us from all unrighteousness. If we say we have not sinned, we make him a liar and his word is not in us.
Notice the simplicity of the scriptural means to be cleansed and the Roman Catholic means. If we say we are without sin, we are liars. So everyone sins. But if we confess our sins, Christ is faithful and righteous, forgiving us our sins and cleansing us from all unrighteousness. If we say we have not sinned . . .
In other words, this is about confessing with the mouth, not ritual deeds, and certainly not purgatorial fires. In other words, the Scripture indicates that one is cleansed at the point that (a) and (b) in the Tridentine path have been peformed; but Trent goes far beyond this in order to maintain its understanding of justification. The problem is that if this is all connected to the way you understand justification, and it's contrary to Scripture, then your understanding of justification is wrong. If that's the case then Rome is wrong, and the Roman Catholic Church is a false church, preaching a false gospel.
Repentance is an acknowledgement of sin that brings about confession, i.e., saying that we have sinned. And this is the biblical pattern of repentance. Remember the sinner and the publican? The publican lists off all of the types of things that make up Roman Catholic penance, but without the element of acknowledgment of sin and the confession thereof. But the sinner lists nothing, only the confession of his sin. What does Christ say to that? The sinner went away forgiven rather than the other. The point being that penance is not jumping through a bunch of ritual hoops and deeds in order to regain favor with God, but in the sorrowful acknowledgment and confession of sin to the One who cleanses you (notice, Christ cleanses you, not the priest--although the Bible does say one can confess sins to other Christians and I have no beef with confessing sins to an elder so that he can affirm Christ's pleasure with you through your repentance).
Indeed, one might say that these things are done as a result of being forgiven, but that is clearly not what Trent is saying. Who burns in purgatory as a result of his forgiveness? The point is that these things bring forgiveness and satisfaction of God's justice to you. They are not things done in gratefulness as a response to forgiveness. Let's not muddy the waters that are clear here. Trent's position, which is the official Roman Catholic position on justification, teaches that all of this is necessary to cleanse us from certain kinds of unrighteousness (i.e., mortal sins), but the Scripture says that "all unrighteousness" is cleansed from us upon our confession of it. Ergo, Trent is in conflict with Scripture and Scripture therefore rejects the Roman Catholic view of justification.
I am astonished that you are so quickly deserting the one who called you by the grace of Christ and are following a different gospel – not that there really is another gospel, but there are some who are disturbing you and wanting to distort the gospel of Christ. But even if we (or an angel from heaven) should preach a gospel contrary to the one we preached to you, let him be condemned to hell! As we have said before, and now I say again, if any one is preaching to you a gospel contrary to what you received, let him be condemned to hell! (Gal 1:6-9)