Holy Baptism is the basis of the whole Christian life, the gateway to life in the Spirit (vitae spiritualisianua), and the door which gives access to the other sacraments. Through Baptism we are freed from sin and reborn as sons of God; we become members of Christ, are incorporated into the Church and made sharers in her mission.
-Catechism of the Catholic Church 1213
Incorporated into the Church by Baptism, the faithful are appointed by their baptismal character to Christian religious worship; reborn as sons of God, they must profess before men the faith they have received from God through the Church.