The Sacrament of Baptism is often called "The door of the Church," because it is the first of the seven sacraments not only in time (since most Catholics receive it as infants) but in priority, since the reception of the other sacraments depends on it. It is the first of the three Sacraments of Initiation, the other two being the Sacrament of Confirmation and the Sacrament of Holy Communion. Once baptized, a person becomes a member of the Church. Traditionally, the rite (or ceremony) of baptism was held outside the doors of the main part of the church, to signify this fact. The Necessity of Baptism:
Christ Himself ordered His disciples to preach the Gospel to all nations and to baptize those who accept the message of the Gospel. In His encounter with Nicodemus (John 3:1-21), Christ made it clear that baptism was necessary for salvation: "Amen, amen I say to thee, unless a man be born again of water and the Holy Ghost, he cannot enter into the kingdom of God." For Catholics, the sacrament is not a mere formality; it is the very mark of a Christian, because it brings us into new life in Christ. Baptism of Desire:
That doesn't mean that only those who have been formally baptized can be saved. From very early on, the Church recognized that there are two other types of baptism besides the baptism of water. The baptism of desire applies both to those who, while wishing to be baptized, die before receiving the sacrament and "Those who, through no fault of their own, do not know the Gospel of Christ or His Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do His will as they know it through the dictates of conscience" (Constitution on the Church, Second Vatican Council). Baptism of Blood:
The baptism of blood is similar to the baptism of desire. It refers to the martyrdom of those believers who were killed for the faith before they had a chance to be baptized. This was a common occurrence in the early centuries of the Church, but also in later times in missionary lands. The baptism of blood has the same effects as the baptism of water. The Form of the Sacrament of Baptism:
While the Church has an extended rite of Baptism which is normally celebrated, which includes roles for both parents and godparents, the essentials of that rite are two: the pouring of water over the head of the person to be baptized (or the immersion of the person in water); and the words "I baptize you in the name of the Father, and of the Son, and of the Holy Spirit."
The Minister of the Sacrament of Baptism:
Since the form of baptism requires just the water and the words, the sacrament, like the Sacrament of Marriage, does not require a priest; any baptized person can baptize another. In fact, when the life of a person is in danger, even a non-baptized person—including someone who does not himself believe in Christ—can baptize, provided that the person performing the baptism follows the form of baptism and intends, by the baptism, to do what the Church does—in other words, to bring the person being baptized into the fullness of the Church. Infant Baptism:
In the Catholic Church today, baptism is most commonly administered to infants. While some other Christians strenuously object to infant baptism, believing that baptism requires assent on the part of the person being baptized, the Eastern Orthodox, Anglicans, Lutherans, and other mainline Protestants also practice infant baptism, and there is evidence that it was practiced from the earliest days of the Church. Since baptism removes both the guilt and the punishment due to Original Sin, delaying baptism until a child can understand the sacrament may put the child's salvation in danger, should he die un-baptized. Adult Baptism:
Adult converts to Catholicism also receive the sacrament, unless they have already received a Christian baptism. (If there is any doubt about whether an adult has already been baptized,...