Baptism, from the Greek word Baptizo meaning to immerse, to bathe, to wash, is a sacrament of the New Law as instituted by Christ in which, by a washing with water, performed by a right-intentioned minister invoking the Holy Trinity a wayfarer on earth is regenerated to divine and supernatural life and aggregated to the Church. Of the three ways in which divine grace may be imparted for justification only Baptism of water is truly a sacrament actively justifying by the very fact of its proper conferral. Baptism of desire is the sacrament in some way truly sought for and terminating whenever possible in the actual reception of the Baptism of water; it justifies on the strength of the genuine desire. Baptism of blood or death suffered for the Christian faith justifies by that very event together with, in the case of adults, at least attrition.

            Baptism, the door to life and to the kingdom of God, is the first sacrament of the New Law offered by Christ to all men that they might have eternal life (Jn 3:5). He entrusted this sacrament and the Gospel to his Church when he told his Apostles: “Go, make disciples of all nations, and baptize them in the name of the Father, and of the Son, and of the Holy Spirit” (Mt 28:19). Thus, Baptism is, above all, the sacrament of that faith by which all men who are enlightened by the Spirit’s grace respond to the Gospel of Christ. That is why the Church believes it is her most basic and necessary duty to inspire all, catechumens, parents of children still to be baptized, and godparents, to that true and living faith by which they adhere to Christ and enter into or confirm their commitment to the new covenant. To accomplish this, the Church prescribes the pastoral instruction of catechumens, the preparation of the children’s parents, the celebration of God’s word, and the profession of baptismal faith.

            Baptism, moreover is the sacrament by which men and women are incorporated into the Church, built into a house where God lives in the Spirit (Ep 2:22), into a royal priesthood (1 P 2:19) and a holy nation. It is a sacramental bond of unity linking all who have been signed by it. Because of that unchangeable effect (signified in the Latin liturgy by the anointing of the baptized person with chrism in the presence of God’s people), the rite of Baptism is held in highest honor by all Christians. It may never lawfully be repeated once it has been validly celebrated, even by our fellow Christians from whom we are separated.

            The cleansing with water by the power of the living Word (Ep 5:26), which Baptism is, makes us sharers in God’s own life (2 P 1:4) and his adopted children (Rm 8:15; Gal 4:5). As proclaimed in the prayers for the blessing of the water, Baptism is a laver of regeneration (Tt 3:5) as sons of God and of birth on high. The invocation of the Trinity over those who are to be baptized has this effect that those who are signed in this name are consecrated to the Trinity and enter into fellowship with the Father, the Son and the Holy Spirit. They are prepared for this high dignity and led to it by the scriptural readings, the prayer of the community, and the threefold profession of faith.

            Far superior to the purifications of the Old Law, Baptism produces all these effects by the power of the mystery of the Lord’s passion and resurrection. Those who are baptized are engrafted in the likeness of Christ’s death (Rm 6:4-5), buried with him in death (ibid.), given life again with him, and with him rise again (Ep 2:6). For Baptism recalls and effects the paschal mystery itself, because by means of it men and women pass from the death of sin into life. Its celebration, therefore, should reflect the joy of the resurrection, especially when it takes place during the Easter Vigil or on a Sunday.

            By the sacrament of Baptism, whenever it is properly conferred in the way the Lord determined, and received with the appropriate dispositions of soul, a person becomes truly incorporated into the crucified and glorified Christ and is reborn to a sharing of the divine life, as the Apostle says: “For you were buried together with him in Baptism, and in him also rose again through faith in the working of God who raised him from the dead” (Col 2:12, cf. Rm 6:4)

            But Baptism, of itself, is only a beginning, a point of departure, for it is wholly directed toward the acquiring of the fullness of life in Christ. Baptism is thus oriented toward a complete profession of faith, a complete incorporation into the system of salvation such as Christ himself wills it to be, and finally, toward a complete participation in Eucharistic communion.

            By his power he is present in the sacraments, so that when a person baptizes it is really Christ himself who baptizes. Thus, by Baptism, we are plunged into the paschal mystery of Christ; we die with him, are buried with him, and rise with him (cf. Rom 6:4; Eph 2:6; Col 3:1-2 1 Tim 2:11 ); we receive the spirit of adoption as children of God “by virtue of which we cry: Abba, Father” (Rm 8:15), and thus become those true adorers whom the Father seeks (cf. Jn 4:23).

            Through Baptism we are formed in the likeness of Christ: “For in one Spirit we are all baptized into one body” ( 1 Cor 12:13). In this sacred rite, a union with Christ’s death and resurrection is both symbolized and brought about: “For we were buried with him by means of baptism unto death.” And if “we have been united with him in the likeness of his death, we shall be so in the likeness of his resurrection also” (Rm 6:4-5).

            Incorporated into the Church through Baptism, the faithful are consecrated by the baptismal character to the exercise of the cult of the Christian religion. Reborn as children of God, they must confess before others the faith which they have received from God through the Church.

            In Baptism neophytes receive forgiveness of sins, adoption as children of God, and the character of Christ, by which they are made members of the Church and for the first time become sharers in the priesthood of their Savior.

            Thus, Baptism, the gateway to the sacraments, is necessary for salvation in fact or at least in intention. It is validly conferred only by washing with true water together with the required formula of words.

-- The Sacraments and Their Celebration.