If an adult comes into the Catholic Church, do they have to be baptized again? If a Catholic leaves the church and becomes a Baptist, why does that person have to be re-baptized?
When I was an active pastor, I conducted baptismal seminars for parents and for godparents. After everyone had a chance to introduce themselves, I would ask each individual, “Do you attend Mass?” I would get various answers from “yes,” “sometimes,” and “no.” I would ask the “no” responders, “Why do you want your child to be baptized if you don’t take part in Mass?” After the initial shock, I would explain the meaning and purpose of baptism.
Baptism by water and by the Holy Spirit is the first of three sacraments of initiation (confirmation and the Eucharist are the other two) that gives access to the other sacraments. It removes and forgives all sins, bestows God’s divine life and grace on the individual, grants a spiritual rebirth, and makes one a member of the church.
Baptism sets up personal relationships with God. The newly baptized become adopted sons or daughters of God with Jesus Christ as their brother. Everyone who is baptized has God’s own divine life in them. All the baptized are part of the body of Christ as St. Paul reminds us, “Now you are the body of Christ and individually members of it” (1 Corinthians 12:27).
Every sacrament has two things: Form and matter. The form of the sacrament is the words that are spoken. For baptism, the form is: “I baptize you in the name of the Father, and of the Son, and of the Holy Spirit.” The matter is the water poured over the head of the recipient.
Traditionally, the one being baptized has water poured over them or is fully immersed in water three times. Additionally, the ceremony includes vows rejecting Satan, vows of the godparents, and the symbols of the white gown and baptismal candle. These additional aspects are important but not required for all baptisms, especially in emergency situations.
Toward the end of the ceremony, the priest or deacon anoints the head of the one being baptized and says, “As Christ was anointed priest, prophet, and king, so may you live always as a member of his body, sharing everlasting life.” As the first letter of Peter reminds us, baptism gives us a share in the royal priesthood of Christ (1 Peter 2:9).
A priest is one who mediates. At every Mass, we take ourselves and others to God’s altar and offer ourselves with Christ to the Father asking for healing or for other blessings from God. A prophet is one who speaks in the name of God. By baptism we are commissioned to speak the message of God to anyone who will listen. A king or queen is one who rules. The first person we have to rule is ourselves, then we can branch out to our family and others.
Baptism makes us a new creature and leaves a spiritual mark of belonging to Christ on our souls. St. Augustine calls it a “character.” This character is like a brand imprinted on a soldier that cannot be removed. The Catechism of the Catholic Church says, “No sin can erase this mark, even if sin prevents baptism from bearing the fruits of salvation … The baptismal seal enables and commits Christians to serve God by a vital participation in the holy liturgy of the church and to exercise their baptismal priesthood by the witness of holy lives and practical charity” (CCC, 1272 and 1273).
If a person comes into the Catholic Church from another Christian Communion that uses the same form and matter that we use in the Catholic Church (see above) then they should not be re-baptized. If another form or matter is used, they should be baptized again.
Most Baptist Churches only recognize the full emersion of the individual to be baptized into a pool of water signifying the dying to the “old person” and emerging as a new person in Christ Jesus. They do not recognize the pouring of water over the head of the person to be baptized. That’s why they re-baptize Catholics and other Christian Church members.