Through this anointing, the confirmand fully receives that gift of the Holy Spirit which he had already received in Baptism in an initial and fundamental way. As the Catechism of the Catholic Church explains, “a seal is a symbol of a person (cf. Gn 38: 18; Song 8: 6), a sign of personal authority (cf. Gn 41: 42), or ownership of an object (cf. Dt 32: 34) …” (CCC, n. 1295). Jesus himself says that “God the Father set his seal” on him (Jn 6: 27). And so we Christians, having been incorporated into the Body of Christ our Lord by faith and Baptism, are marked by the seal of the Spirit when we receive this anointing. The Apostle Paul explicitly teaches this in speaking to the Christians of Corinth: “It is God who establishes us with you in Christ, and has commissioned us; he has put his seal upon us and given us his Spirit in our hearts as a guarantee” (2 Cor 1: 21-22; cf. Eph 1: 13-14; 4: 30).
The seal of the Holy Spirit therefore signifies and brings about the disciple’s total belonging to Jesus Christ, his being always at the latter’s service in the Church, and at the same time it implies the promise of divine protection in the trials he will have to endure to witness to his faith in the world.
Jesus himself foretold this, shortly before his Passion: “They will deliver you up to councils; and you will be beaten in synagogues; and you will stand before governors and kings for my sake, to bear testimony before them…. And when they bring you to trial and deliver you up, do not be anxious beforehand what you are to say; but say whatever is given you in that hour, for it is not you who speak, but the Holy Spirit” (Mk 13: 9, 11ff.).