What are the two basic elements required for the forgiveness of a Christian's sins to occur in the sacrament of Penance?
What is required for the forgiveness of sins is the person who undergoes conversion and the priest who in God's name gives him absolution from his sins.
What must I bring to a confession?
Essential elements of every confession are an examination of conscience, contrition, a purpose of amendment, confession, and penance.
The examination of conscience should be done thoroughly, but it can never be exhaustive. No one can be absolved from his sin without real contrition, merely on the basis of "lip-service". Equally indispensable is the purpose of amendment, the resolution not to commit that sin again in the future. The sinner absolutely must declare the sin to the confessor and, thus, confess to it. The final essential element of confession is the atonement or penance that the confessor imposes on the sinner to make restitution for the harm done.(YOUCAT questions 231 & 232)
Dig Deeper: CCC section (1450-1460) and other references here.
Part 2: The Celebration of the Christian Mystery (1066 - 1690)
Section 2: The Seven Sacraments of the Church (1210 - 1690)
Chapter 2: The Sacraments of Healing (1420 - 1532)
Article 4: The Sacrament of Penance and Reconciliation (1422 - 1498)
VII. THE ACTS OF THE PENITENT ⇡
"Penance requires ... the sinner to endure all things willingly, be contrite of heart, confess with the lips, and practice complete humility and fruitful satisfaction."49
49.
Roman Catechism II,V,21; cf. Council of Trent (1551): DS 1673.
Contrition ⇡
Among the penitent's acts contrition occupies first place. Contrition is "sorrow of the soul and detestation for the sin committed, together with the resolution not to sin again."50
50.
Council of Trent (1551): DS 1676.
When it arises from a love by which God is loved above all else, contrition is called "perfect" (contrition of charity). Such contrition remits venial sins; it also obtains forgiveness of mortal sins if it includes the firm resolution to have recourse to sacramental confession as soon as possible.51
51.
Cf. Council of Trent (1551): DS 1677.
The contrition called "imperfect" (or "attrition") is also a gift of God, a prompting of the Holy Spirit. It is born of the consideration of sin's ugliness or the fear of eternal damnation and the other penalties threatening the sinner (contrition of fear). Such a stirring of conscience can initiate an interior process which, under the prompting of grace, will be brought to completion by sacramental absolution. By itself however, imperfect contrition cannot obtain the forgiveness of grave sins, but it disposes one to obtain forgiveness in the sacrament of Penance.52
52.
Cf. Council of Trent (1551): DS 1678; 1705.
The reception of this sacrament ought to be prepared for by an examination of conscience made in the light of the Word of God. The passages best suited to this can be found in the Ten Commandments, the moral catechesis of the Gospels and the apostolic Letters, such as the Sermon on the Mount and the apostolic teachings.53
53.
Cf. Mt 5-7; Rom 12-15; 1 Cor 12-13; Gal 5; Eph 4-6; etc.
The confession of sins ⇡
The confession (or disclosure) of sins, even from a simply human point of view, frees us and facilitates our reconciliation with others. Through such an admission man looks squarely at the sins he is guilty of, takes responsibility for them, and thereby opens himself again to God and to the communion of the Church in order to make a new future possible.
Confession to a priest is an essential part of the sacrament of Penance: "All mortal sins of which penitents after a diligent self-examination are conscious must be recounted by them in confession, even if they are most secret and have been committed against the last two precepts of the Decalogue; for these sins sometimes wound the soul more grievously and are more dangerous than those which are committed openly."54 When Christ's faithful strive to confess all the sins that they can remember, they undoubtedly place all of them before the divine mercy for pardon. But those who fail to do so and knowingly withhold some, place nothing before the divine goodness for remission through the mediation of the priest, "for if the sick person is too ashamed to show his wound to the doctor, the medicine cannot heal what it does not know."55
54.
Council of Trent (1551): DS 1680 (ND 1626); cf. Ex 20:17; Mt 5:28.
55.
Council of Trent (1551): DS 1680 (ND 1626); cf. St. Jerome, In Eccl. 10,11:PL 23:1096.
According to the Church's command, "after having attained the age of discretion, each of the faithful is bound by an obligation faithfully to confess serious sins at least once a year."56 Anyone who is aware of having committed a mortal sin must not receive Holy Communion, even if he experiences deep contrition, without having first received sacramental absolution, unless he has a grave reason for receiving Communion and there is no possibility of going to confession.57 Children must go to the sacrament of Penance before receiving Holy Communion for the first time.58
56.
Cf. CIC, Can. 989; Council of Trent (1551): DS 1683; DS 1708.
57.
Cf. Council of Trent (1551): DS 1647; 1661; CIC, can. 916; CCEO, can. 711.
58.
Cf. CIC, can. 914.
Without being strictly necessary, confession of everyday faults (venial sins) is nevertheless strongly recommended by the Church.59 Indeed the regular confession of our venial sins helps us form our conscience, fight against evil tendencies, let ourselves be healed by Christ and progress in the life of the Spirit. By receiving more frequently through this sacrament the gift of the Father's mercy, we are spurred to be merciful as he is merciful:60 Whoever confesses his sins ... is already working with God. God indicts your sins; if you also indict them, you are joined with God. Man and sinner are, so to speak, two realities: when you hear "man" — this is what God has made; when you hear "sinner" — this is what man himself has made. Destroy what you have made, so that God may save what he has made. ... When you begin to abhor what you have made, it is then that your good works are beginning, since you are accusing yourself of your evil works. The beginning of good works is the confession of evil works. You do the truth and come to the light.61
59.
Cf. Council of Trent: DS 1680; CIC, can. 988 § 2.
60.
Cf. Lk 6:36.
61.
St. Augustine, In Jo. ev. 12,13:PL 35,1491.
Satisfaction ⇡
Many sins wrong our neighbor. One must do what is possible in order to repair the harm (e.g., return stolen goods, restore the reputation of someone slandered, pay compensation for injuries). Simple justice requires as much. But sin also injures and weakens the sinner himself, as well as his relationships with God and neighbor. Absolution takes away sin, but it does not remedy all the disorders sin has caused.62 Raised up from sin, the sinner must still recover his full spiritual health by doing something more to make amends for the sin: he must "make satisfaction for" or "expiate" his sins. This satisfaction is also called "penance."
62.
Cf. Council of Trent (1551): DS 1712.
The penance the confessor imposes must take into account the penitent's personal situation and must seek his spiritual good. It must correspond as far as possible with the gravity and nature of the sins committed. It can consist of prayer, an offering, works of mercy, service of neighbor, voluntary self-denial, sacrifices, and above all the patient acceptance of the cross we must bear. Such penances help configure us to Christ, who alone expiated our sins once for all. They allow us to become co-heirs with the risen Christ, "provided we suffer with him."63 The satisfaction that we make for our sins, however, is not so much ours as though it were not done through Jesus Christ. We who can do nothing ourselves, as if just by ourselves, can do all things with the cooperation of "him who strengthens" us. Thus man has nothing of which to boast, but all our boasting is in Christ ... in whom we make satisfaction by bringing forth "fruits that befit repentance." These fruits have their efficacy from him, by him they are offered to the Father, and through him they are accepted by the Father.64
63.
Rom 8:17; Rom 3:25; 1 Jn 2:1-2; cf. Council of Trent (1551): DS 1690.
64.
Council of Trent (1551): DS 1691; cf. Phil 4:13; 1 Cor 1:31; 2 Cor 10:17; Gal 6:14; Lk 3:8.