Of the seven sacraments, Baptism, Confirmation and Eucharist are referred to as the “sacraments of Christian initiation” because it is by reception of these three sacraments that a person is fully received into communion with the Church and is made a partaker in the divine life of Christ. Of the three sacraments of initiation, Baptism and Confirmation are unrepeatable and give the recipient an indelible mark.
The sharing in the divine nature given to men through the grace of Christ bears a certain likeness to the origin, development, and nourishing of natural life…by means of these sacraments of Christian initiation, they thus receive in increasing measure the treasures of divine life and advance toward the perfection of charity” (CCC 1212).
For Further Discussion: Baptism in the Old Testament; Baptism in Transition; the Baptism of Christ; Baptism as a Sacrment of Initiation; Baptism of Infants; What is Confirmation? Form and Matter; Who Can be Confirmed? When Does One Get Confirnmed? The Rite of Christian Initiation; The Minister of the Sacrament of Confirmation; Confirmation in Scripture