“Go and make disciples of all nations, baptizing then in the name of the Father, and of the Son, and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, until the end of the age.” MT 28:19-28
The first of the seven sacraments, and the “door” which gives access to the other sacraments. Baptism is the first and chief sacrament of forgiveness of sins because it unites us with Christ, who died for our sins and rose for our justification. Baptism, Confirmation, and Eucharist constitute the “sacraments of initiation” by which a believer receives the remission of original and personal sin, begins a new life in Christ and the Holy Spirit, and is incorporated into the Church, the Body of Christ.
Before starting his public ministry, Jesus submitted himself to the baptism given by John the Baptist. The waters did not purify him; he cleansed the waters. . . . Jesus did not need to be baptized because he was totally faithful to the will of his Father and free from sin. However, he wanted to show his solidarity with human beings in order to reconcile them to the Father. By commanding his disciples to baptize all nations, he established the means by which people would die to sin – Original and actual – and begin to live a new life with God. ~ from the United States Catholic Catechism for Adults.
“The fruit of Baptism, or baptismal grace, is a rich reality that includes forgiveness of original sin and all personal sins, birth into the new life by which man becomes an adoptive son of the Father, a member of Christ and a temple of the Holy Spirit. By this very fact the person baptized is incorporated into the Church, the Body of Christ, and made a sharer in the priesthood of Christ” – Catechism of the Catholic Church 1279