Today’s Catechism sections discuss the priest as the minister of the Sacrament of Penance. Supporting material comes from the “Summa Theologica”.

VIII. The Minister of This Sacrament

1461 Since Christ entrusted to his apostles the ministry of reconciliation,65 bishops who are their successors, and priests, the bishops' collaborators, continue to exercise this ministry. Indeed bishops and priests, by virtue of the sacrament of Holy Orders, have the power to forgive all sins "in the name of the Father, and of the Son, and of the Holy Spirit."

1462 Forgiveness of sins brings reconciliation with God, but also with the Church. Since ancient times the bishop, visible head of a particular Church, has thus rightfully been considered to be the one who principally has the power and ministry of reconciliation: he is the moderator of the penitential discipline.66 Priests, his collaborators, exercise it to the extent that they have received the commission either from their bishop (or religious superior) or the Pope, according to the law of the Church.67

1463 Certain particularly grave sins incur excommunication, the most severe ecclesiastical penalty, which impedes the reception of the sacraments and the exercise of certain ecclesiastical acts, and for which absolution consequently cannot be granted, according to canon law, except by the Pope, the bishop of the place or priests authorized by them.68 In danger of death any priest, even if deprived of faculties for hearing confessions, can absolve from every sin and excommunication.69

1464 Priests must encourage the faithful to come to the sacrament of Penance and must make themselves available to celebrate this sacrament each time Christians reasonably ask for it.70

1465 When he celebrates the sacrament of Penance, the priest is fulfilling the ministry of the Good Shepherd who seeks the lost sheep, of the Good Samaritan who binds up wounds, of the Father who awaits the prodigal son and welcomes him on his return, and of the just and impartial judge whose judgment is both just and merciful. The priest is the sign and the instrument of God's merciful love for the sinner.

1466 The confessor is not the master of God's forgiveness, but its servant. The minister of this sacrament should unite himself to the intention and charity of Christ.71 He should have a proven knowledge of Christian behavior, experience of human affairs, respect and sensitivity toward the one who has fallen; he must love the truth, be faithful to the Magisterium of the Church, and lead the penitent with patience toward healing and full maturity. He must pray and do penance for his penitent, entrusting him to the Lord's mercy.

1467 Given the delicacy and greatness of this ministry and the respect due to persons, the Church declares that every priest who hears confessions is bound under very severe penalties to keep absolute secrecy regarding the sins that his penitents have confessed to him. He can make no use of knowledge that confession gives him about penitents' lives.72 This secret, which admits of no exceptions, is called the "sacramental seal," because what the penitent has made known to the priest remains "sealed" by the sacrament.

IN BRIEF

1495 Only priests who have received the faculty of absolving from the authority of the Church can forgive sins in the name of Christ.

In the “Summa Theologica” (Supplement, 8, 1), St. Thomas Aquinas discusses the minister of the Sacrament of Penance: the Priest.

Article 1. Whether it is necessary to confess to a priest?

Objection 1. It would seem that it is not necessary to confess to a priest. For we are not bound to confession, except in virtue of its Divine institution. Now its Divine institution is made known to us (James 5:16): "Confess your sins, one to another," where there is no mention of a priest. Therefore it is not necessary to confess to a priest.

Objection 2. Further, Penance is a necessary sacrament, as is also Baptism. But any man is the minister of Baptism, on account of its necessity. Therefore any man is the minister of Penance. Now confession should be made to the minister of Penance. Therefore it suffices to confess to anyone.

Objection 3. Further, confession is necessary in order that the measure of satisfaction should be imposed on the penitent. Now, sometimes another than a priest might be more discreet than many priests are in imposing the measure of satisfaction on the penitent. Therefore it is not necessary to confess to a priest.

Objection 4. Further, confession was instituted in the Church in order that the rectors might know their sheep by sight. But sometimes a rector or prelate is not a priest. Therefore confession should not always be made to a priest.

On the contrary, The absolution of the penitent, for the sake of which he makes his confession, is imparted by none but priests to whom the keys are entrusted. Therefore confession should be made to a priest.

Further, confession is foreshadowed in the raising of the dead Lazarus to life. Now our Lord commanded none but the disciples to loose Lazarus (John 11:44). Therefore confession should be made to a priest.

I answer that, The grace which is given in the sacraments, descends from the Head to the members. Wherefore he alone who exercises a ministry over Christ's true body is a minister of the sacraments, wherein grace is given; and this belongs to a priest alone, who can consecrate the Eucharist. Therefore, since grace is given in the sacrament of Penance, none but a priest is the minister of the sacrament: and consequently sacramental confession which should be made to a minister of the Church, should be made to none but a priest.

Reply to Objection 1. James speaks on the presupposition of the Divine institutions: and since confession had already been prescribed by God to be made to a priest, in that He empowered them, in the person of the apostles, to forgive sins, as related in John 20:23, we must take the words of James as conveying an admonishment to confess to priests.

Reply to Objection 2. Baptism is a sacrament of greater necessity than Penance, as regards confession and absolution, because sometimes Baptism cannot be omitted without loss of eternal salvation, as in the case of children who have not come to the use of reason: whereas this cannot be said of confession and absolution, which regard none but adults, in whom contrition, together with the purpose of confessing and the desire of absolution, suffices to deliver them from everlasting death. Consequently there is no parity between Baptism and confession.

Reply to Objection 3. In satisfaction we must consider not only the quantity of the punishment but also its power, inasmuch as it is part of a sacrament. In this way it requires a dispenser of the sacraments, though the quantity of the punishment may be fixed by another than a priest.

Reply to Objection 4. It may be necessary for two reasons to know the sheep by sight. First, in order to register them as members of Christ's flock, and to know the sheep by sight thus belongs to the pastoral charge and care, which is sometimes the duty of those who are not priests. Secondly, that they may be provided with suitable remedies for their health; and to know the sheep by sight thus belongs to the man, i.e. the priest, whose business it is to provide remedies conducive to health, such as the sacrament of the Eucharist, and other like things. It is to this knowledge of the sheep that confession is ordained.

Footnotes

65 Cf. In 20:23; ⇒ 2 Cor 5:18.
66 Cf. LG 26 # 3.
67 Cf. ⇒ CIC cann. 844; ⇒ 967-969; ⇒ 972; CCEO, can. 722 ## 3-4.
68 Cf. ⇒ CIC, cann. 1331; ⇒ 1354-1357; CCEO, can. 1431; 1434; 1420.
69 Cf. ⇒ CIC, can. 976; CCEO, can. 725.
70 Cf. ⇒ CIC, can. 486; CCEO, can. 735; PO 13.
71 Cf. PO 13.
72 Cf. ⇒ CIC, can. 1388 # 1; CCEO, can. 1456.