CIC 698 The seal is a symbol close to that of anointing. “The Father has set his seal” on Christ and also seals us in him.1 Because this seal indicates the indelible effect of the anointing with the Holy Spirit in the sacraments of Baptism, Confirmation, and Holy Orders, the image of the seal (sphragis) has been used in some theological traditions to express the indelible “character” imprinted by these three unrepeatable sacraments.

CIC 1274 The Holy Spirit has marked us with the seal of the Lord (“Dominicus character”) “for the day of redemption.”2 “Baptism indeed is the seal of eternal life.”3 The faithful Christian who has “kept the seal” until the end, remaining faithful to the demands of his Baptism, will be able to depart this life “marked with the sign of faith,”4 with his baptismal faith, in expectation of the blessed vision of God – the consummation of faith – and in the hope of resurrection.

CIC 1296 Christ himself declared that he was marked with his Father’s seal.5 Christians are also marked with a seal: “It is God who establishes us with you in Christ and has commissioned us; he has put his seal on us and given us his Spirit in our hearts as a guarantee.”6 This seal of the Holy Spirit marks our total belonging to Christ, our enrollment in his service for ever, as well as the promise of divine protection in the great eschatological trial.7

CIC 1454 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.8

CIC 2842 This “as” is not unique in Jesus’ teaching: “You, therefore, must be perfect, as your heavenly Father is perfect”; “Be merciful, even as your Father is merciful”; “A new commandment I give to you, that you love one another, even as I have loved you, that you also love one another.”9 It is impossible to keep the Lord’s commandment by imitating the divine model from outside; there has to be a vital participation, coming from the depths of the heart, in the holiness and the mercy and the love of our God. Only the Spirit by whom we live can make “ours” the same mind that was in Christ Jesus.10 Then the unity of forgiveness becomes possible and we find ourselves “forgiving one another, as God in Christ forgave” us.11

1 Jn 6:27; cf. 2 Cor 1:22; Eph 1:13; 4:3.
2 St. Augustine, Ep. 98, 5: PL 33, 362; Eph 4:30; cf. 1:13-14; 2 Cor 1:21-22.
3 St. Irenaeus, Dem ap. 3: SCh 62, 32.
4 Roman Missal, EP I (Roman Canon) 97.
5 Cf. Jn 6:27.
6 2 Cor 1:21-22; cf. Eph 1:13; 4,30.
7 Cf. Rev 7:2-3; 9:4; Ezek 9:4-6.
8 Cf. Mt 5-7; Rom 12-15; 1 Cor 12-13; Gal 5; Eph 4-6; etc.
9 Mt 5:48; Lk 6:36; Jn 13:34.
10 Cf. Gal 5:25; Phil 2:1,5.
11 Eph 4:32.