Penance is a particular act, or acts, considered as satisfaction offered to God as reparation for sin committed.¹ Penance may involve mortification, such as wearing an irritating shirt woven of coarse animal hair,² prayer (e.g., the Rosary), or a religious pilgrimage to a shrine of Christ or Mary,³ or any number of other deeds.

According to The Catholic Encyclopedia, Jesus Christ Himself instituted the sacrament of penance for "the pardon of sins committed after baptism."⁴ Thus, "In the sacrament of penance, the faithful obtain from the mercy of God pardon for their sins against Him.…"⁵

As noted, the sacrament of penance is designed specifically to deal with sins committed after baptism. Why? Because the grace that is received or infused in baptism can be entirely lost by mortal ("deadly") sin. Mortal sin is held to be deadly because it actually destroys the grace of God within a person, making salvation necessary again. Thus, a new sacrament (penance) is necessary in order to restore an individual to the state of grace first received at baptism.

In fact, without penance a person cannot be restored to salvation. For example, penance is related to the concept of justification in such a way that it actually "restores" the process of justification. In one sense, this is why the Council of Trent actually referred to the sacrament of penance as the "second plank" of justification.⁶

Thus, salvation through good works can also be seen in the doctrine of penance. Because mortal or "deadly" sin cancels the ongoing process of infusing grace, justification and/or salvation in the life of the Catholic believer, all these must be restored. Thus, "...the result of mortal sin is the loss of sanctifying grace, the loss of the gifts of the Holy Spirit, remorse, and the punitive effect of eternal separation from God. To avoid these consequences, the reception of the Sacrament of Penance is required to return to the love of God."⁷

In other words, apart from performing the sacrament of penance, a Catholic who commits mortal sin is destined for eternal punishment in hell. Escaping such a fate results from the penitent acts of the believer, i.e., a form of salvation by works.

But none of this is biblical. Biblically, prior to salvation all sin is mortal. Even the smallest sin is sufficient to condemn a person eternally. But after salvation no sin is mortal, no matter how grave, because Christ paid the full divine penalty for all sin on the cross—and because this complete forgiveness has been given to the believer. Further, according to Scripture, salvation is based on God’s grace and election—not personal merit or works. If salvation is by grace and election, then it depends entirely on God and therefore no saved person can ever be lost and no mortal sin can ever cancel a person’s justification.

What this means is that Catholics who believe their mortal sins are forgiven by the work of penance are being deceived. If they are truly saved, then their mortal sins—all of them—are already fully forgiven by the death of Christ solely through their faith in Jesus.

But if they are not saved, then all the penance in the world cannot forgive their sins, whether such sins are "mortal" or the less serious "venial" ones. Biblically, it is faith in Christ alone which forgives sins—not penance or any other sacrament.⁸

Although Catholicism maintains that the works of satisfaction accomplished by the penitent sinner do not give him intrinsic merit (merit of condignity), they do claim they give him other merit (merit of congruity). These are works of satisfaction supposedly done through the power of Jesus and the grace of God. But the key point is that they are works done by an individual—they are his/her works and they are meritorious. In the end, it is still my work and my merit that makes it possible for God to restore me to the process of justification and/or salvation. In the end it is something I do that keeps me out of hell.

Biblically, of course, it is the merit of Jesus Christ alone that reconciles us, justifies us, and assures our entrance into heaven.

The above discussion proves that Catholicism does teach salvation occurs, at least in part, through the sacraments—in other words, works of merit performed by individual Catholics in order to help secure their own redemption.

The above teachings are why "The sacraments as works of human merit, which must be mediated through the church, represent a denial of justification by faith alone and an infringement upon the sovereign freedom of God."⁹

But Rome also teaches that sacraments function in certain ways irrespective of the spiritual condition of the priest or layperson, functioning ex opere operato; in essence, they "work by their own working" to "confer grace to the soul":

But in another sense, the sacraments may be said to not produce grace. They:

Although Catholicism objects to the occasional Protestant assertion that the sacraments function as a kind of magic, it is difficult to deny this charge entirely.¹² R. C. Sproul believes it is incorrect to finally equate the sacraments with magic, but he nevertheless remarks, "...if you made a serious analysis of the essence of magic and the essence of the [Catholic] Doctrine of the Lord’s Supper, you would find a great many parallels."¹³

In essence, what the sacraments do effect would seem to be a form of "mechanical" sanctification.

Regardless, the Council of Trent, whose decrees remain authoritative, declared as anathema (divinely cursed) anyone who would deny the seven sacraments of Rome: "If anyone says that the sacraments...were not all instituted by our Lord Jesus Christ, or that there are more or less than seven...or that any one of these seven is not truly and intrinsically a sacrament, let him be anathema."¹⁴ Further, "if anyone says that the sacraments... are not necessary for salvation... and that without them... men obtain from God through faith alone the grace of justification... let him be anathema."¹⁵ Further, Canon Five reads, "If anyone says that baptism is optional, that is, not necessary for salvation, let him be anathema."¹⁶

In conclusion, the sacraments of Rome are proof that a system of works salvation is taught and therefore that the Catholic Church teaches "another Gospel" (Galatians 1:8,9). In the end, salvation is procured by 1) God’s grace, 2) individual faith and 3) works, i.e., the sacraments.