CIC 433 The name of the Savior God was invoked only once in the year by the high priest in atonement for the sins of Israel, after he had sprinkled the mercy seat in the Holy of Holies with the sacrificial blood. The mercy seat was the place of God’s presence.1 When St. Paul speaks of Jesus whom “God put forward as an expiation by his blood”, he means that in Christ’s humanity “God was in Christ reconciling the world to himself.”2

CIC 602 Consequently, St. Peter can formulate the apostolic faith in the divine plan of salvation in this way: “You were ransomed from the futile ways inherited from your fathers. .. with the precious blood of Christ, like that of a lamb without blemish or spot. He was destined before the foundation of the world but was made manifest at the end of the times for your sake.”3 Man’s sins, following on original sin, are punishable by death.4 By sending his own Son in the form of a slave, in the form of a fallen humanity, on account of sin, God “made him to be sin who knew no sin, so that in him we might become the righteousness of God.”5

CIC 827 “Christ, ‘holy, innocent, and undefiled,’ knew nothing of sin, but came only to expiate the sins of the people. The Church, however, clasping sinners to her bosom, at once holy and always in need of purification, follows constantly the path of penance and renewal.”6 All members of the Church, including her ministers, must acknowledge that they are sinners.7 In everyone, the weeds of sin will still be mixed with the good wheat of the Gospel until the end of time.8 Hence the Church gathers sinners already caught up in Christ’s salvation but still on the way to holiness:
The Church is therefore holy, though having sinners in her midst, because she herself has no other life but the life of grace. If they live her life, her members are sanctified; if they move away from her life, they fall into sins and disorders that prevent the radiation of her sanctity. This is why she suffers and does penance for those offenses, of which she has the power to free her children through the blood of Christ and the gift of the Holy Spirit.9

CIC 859 Jesus unites them to the mission he received from the Father. As “the Son can do nothing of his own accord,” but receives everything from the Father who sent him, so those whom Jesus sends can do nothing apart from him,10 from whom they received both the mandate for their mission and the power to carry it out. Christ’s apostles knew that they were called by God as “ministers of a new covenant,” “servants of God,” “ambassadors for Christ,” “servants of Christ and stewards of the mysteries of God.”11

CIC 981 After his Resurrection, Christ sent his apostles “so that repentance and forgiveness of sins should be preached in his name to all nations.”12 The apostles and their successors carry out this “ministry of reconciliation,” not only by announcing to men God’s forgiveness merited for us by Christ, and calling them to conversion and faith; but also by communicating to them the forgiveness of sins in Baptism, and reconciling them with God and with the Church through the power of the keys, received from Christ:13
[The Church] has received the keys of the Kingdom of heaven so that, in her, sins may be forgiven through Christ’s blood and the Holy Spirit’s action. In this Church, the soul dead through sin comes back to life in order to live with Christ, whose grace has saved us.14

CIC 1214 This sacrament is called Baptism, after the central rite by which it is carried out: to baptize (Greek baptizein) means to “plunge” or “immerse”; the “plunge” into the water symbolizes the catechumen’s burial into Christ’s death, from which he rises up by resurrection with him, as “a new creature.”15

CIC 1265 Baptism not only purifies from all sins, but also makes the neophyte “a new creature,” an adopted son of God, who has become a “partaker of the divine nature,”16 member of Christ and co-heir with him,17 and a temple of the Holy Spirit.18

CIC 1424 It is called the sacrament of confession, since the disclosure or confession of sins to a priest is an essential element of this sacrament. In a profound sense it is also a “confession” – acknowledgment and praise – of the holiness of God and of his mercy toward sinful man.
It is called the sacrament of forgiveness, since by the priest’s sacramental absolution God grants the penitent “pardon and peace.”19
It is called the sacrament of Reconciliation, because it imparts to the sinner the live of God who reconciles: “Be reconciled to God.”20 He who lives by God’s merciful love is ready to respond to the Lord’s call: “Go; first be reconciled to your brother.”21

CIC 1442 Christ has willed that in her prayer and life and action his whole Church should be the sign and instrument of the forgiveness and reconciliation that he acquired for us at the price of his blood. But he entrusted the exercise of the power of absolution to the apostolic ministry which he charged with the “ministry of reconciliation.”22 The apostle is sent out “on behalf of Christ” with “God making his appeal” through him and pleading: “Be reconciled to God.”23

CIC 1461 Since Christ entrusted to his apostles the ministry of reconciliation,24 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.”

CIC 1999 The grace of Christ is the gratuitous gift that God makes to us of his own life, infused by the Holy Spirit into our soul to heal it of sin and to sanctify it. It is the sanctifying or deifying grace received in Baptism. It is in us the source of the work of sanctification:25
Therefore if any one is in Christ, he is a new creation; the old has passed away, behold, the new has come. All this is from God, who through Christ reconciled us to himself.26

CIC 2844 Christian prayer extends to the forgiveness of enemies,27 transfiguring the disciple by configuring him to his Master. Forgiveness is a high-point of Christian prayer; only hearts attuned to God’s compassion can receive the gift of prayer. Forgiveness also bears witness that, in our world, love is stronger than sin. The martyrs of yesterday and today bear this witness to Jesus. Forgiveness is the fundamental condition of the reconciliation of the children of God with their Father and of men with one another.28

1 Cf. Ex 25:22; Lev 16:2,15-16; Num 7:89; Sir 50:20; Heb 9:5,7.
2 Rom 3:25; 2 Cor 5:19.
3 I Pt 1:18-20.
4 Cf. Rom 5:12; I Cor 15:56.
5 2 Cor 5:21; cf. Phil 2:7; Rom 8:3.
6 LG 8 § 3; Cf. UR 3; 6; Heb 2:17; 726; 2 Cor 5:21.
7 Cf. 1 Jn 1:8-10.
8 Cf. Mt 13:24-30.
9 Paul VI, CPG § 19.
10 Jn 5:19, 30; cf. Jn 15:5.
11 2 Cor 3:6; 6:4; 5:20; 1 Cor 4:1.
12 Lk 24:47.
13 2 Cor 5:18.
14 St. Augustine, Sermo 214,11:PL 38,1071-1072.
15 2 Cor 5:17; Gal 6:15; Cf. Rom 6:34; Col 2:12.
16 2 Cor 5:17; 2 Pet 1:4; cf. Gal 4:5-7.
17 Cf. l Cor 6:15; 12:27; Rom 8:17.
18 Cf. l Cor 6:19.
19 OP 46 formula of absolution.
20 2 Cor 5:20.
21 MT 5:24.
22 2 Cor 5:18.
23 2 Cor 5:20.
24 Cf. In 20:23; 2 Cor 5:18.
25 Cf. Jn 4:14; 7:38-39.
26 2 Cor 5:17-18.
27 Cf. Mt 5:43-44.
28 Cf. 2 Cor 5:18-21; John Paul II, DM 14.