Thomas Aquinas

“ A thing is absolutely necessary for salvation, if no one can obtain salvation without it, as, for example, the grace of Christ, and the sacrament of Baptism, whereby a man is born again in Christ. The sacrament of Penance is necessary on a supposition, for it is necessary, not for all, but for those who are in sin. ”

“ In this way a man may be displeased at having sinned, and be pleased at his displeasure together with his hope for pardon, so that his very sorrow is a matter of joy. Hence Augustine says [*De vera et falsa Poenitentia, the authorship of which is unknown] : "The penitent should ever grieve and rejoice at his grief."
If, however, sorrow were altogether incompatible with joy, this would prevent the continuance, not of habitual penance, but only of actual penance. ”

“ Because a man is a mocker and not a penitent, who, "while doing penance," does what he repents having done, or intends to do again what he did before, or even commits actually the same or another kind of sin. But if a man sin afterwards either by act or intention, this does not destroy the fact that his former penance was real, because the reality of a former act is never destroyed by a subsequent contrary act: for even as he truly ran who afterwards sits, so he truly repented who subsequently sins. ”

“ Wherefore, just as the priest in baptizing anyone, declares by deed and word that the person is washed inwardly, and this not only significatively but also effectively, so also when he says: "I absolve thee," he declares the man to be absolved not only significatively but also effectively. And yet he does not speak as of something uncertain, because just as the other sacraments of the New Law have, of themselves, a sure effect through the power of Christ's Passion, which effect, nevertheless, may be impeded on the part of the recipient, so is it with this sacrament. ”

“ Baptism, which is the spiritual birth, Confirmation which is the spiritual growth, the Eucharist which is the spiritual food; whereas Penance is ordained to man's salvation accidentally as it were, and on something being supposed, viz. sin: for unless man were to sin actually, he would not stand in need of Penance and yet he would need Baptism, Confirmation, and the Eucharist; even as in the life of the body, man would need no medical treatment, unless he were ill, and yet life, birth, growth, and food are, of themselves, necessary to man. ”

“ To hide one's sins may happen in two ways: first, in the very act of sinning. Now it is worse to sin in public than in private, both because a public sinner seems to sin more from contempt, and because by sinning he gives scandal to others. ”

“ Consequently Penance holds the second place with regard to the state of integrity which is bestowed and safeguarded by the aforesaid sacraments, so that it is called metaphorically "a second plank after shipwreck." For just as the first help for those who cross the sea is to be safeguarded in a whole ship, while the second help when the ship is wrecked, is to cling to a plank; so too the first help in this life's ocean is that man safeguard his integrity, while the second help is, if he lose his integrity through sin, that he regain it by means of Penance. ”

“ Wherefore, such human acts as are in these sacraments, are not the essential matter of the sacrament, but are dispositions thereto. On the other hand, in those sacraments whose effect corresponds to that of some human act, the sensible human act itself takes the place of matter, as in the case of Penance and Matrimony, even as in bodily medicines, some are applied externally, such as plasters and drugs, while others are acts of the person who seeks to be cured, such as certain exercises. ”

“ Consequently it is necessary for the sinner's salvation that sin be taken away from him; which cannot be done without the sacrament of Penance, wherein the power of Christ's Passion operates through the priest's absolution and the acts of the penitent, who co-operates with grace unto the destruction of his sin. ”

“ For since true Penance requires charity, without which sins are not taken away, they thought that charity once possessed could not be lost, and that, consequently, Penance, if true, could never be removed by sin, so that it should be necessary to repeat it. ”

“ Some are to be found who think they ought often to do penance, who take liberties with Christ: for if they were truly penitent, they would not think of doing penance over again, since there is but one Penance even as there is but one Baptism. ”

“ Further, Gregory says (Hom. xxxiv in Evang.) : "Penance consists in deploring past sins, and in not committing again those we have deplored": and Isidore says (De Summo Bono ii) : "He is a mocker and no penitent who still does what he has repented of." If, therefore, a man is truly penitent, he will not sin again. Therefore Penance cannot be repeated.
Objection 5: Further, just as Baptism derives its efficacy from the Passion of Christ, so does Penance. Now Baptism is not repeated, on account of the unity of Christ's Passion and death. Therefore in like manner Penance is not repeated. ”

“ It is not every reception of the Holy Ghost that requires an imposition of hands, since even in Baptism man receives the Holy Ghost, without any imposition of hands: it is at the reception of the fulness of the Holy Ghost which belongs to Confirmation that an imposition of hands is required. ”

“ Now the sacrament of Penance is ordained, not that man may receive some abundance of grace, but that his sins may be taken away; and therefore no imposition of hands is required for this sacrament, as neither is there for Baptism, wherein nevertheless a fuller remission of sins is bestowed. ”

“ Therefore it is evident that after sin the sacrament of Penance is necessary for salvation, even as bodily medicine after man has contracted a dangerous disease.
Reply to Objection 1: This gloss should apparently be understood as referring to the man who has a good will unimpaired by sin, for such a man has no cause for sorrow: but as soon as the good will is forfeited through sin, it cannot be restored without that sorrow whereby a man sorrows for his past sin, and which belongs to Penance. ”

“ The three sacraments which precede Penance refer to the ship in its integrity, i.e. to man's state of integrity, with regard to which Penance is called a second plank.
Art. 7 - Whether this sacrament was suitably instituted in the New Law? Objection 1: It would seem that this sacrament was unsuitably instituted in the New Law. Because those things which belong to the natural law need not to be instituted. Now it belongs to the natural law that one should repent of the evil one has done: for it is impossible to love good without grieving for its contrary. ”

“ Wherefore our Lord expressed both: for He said to Peter (Mat. 16:19) : "Whatsoever thou shalt loose on earth," etc., and to His disciples (Jn. 20:23) : "Whose sins you shall forgive, they are forgiven them." ”