Baptism makes one a Christian and in doing so requires one to live as befits a child of God. The grace of the Spirit given in baptism empowers one to do this, as natural begetting empowers one to do what comes naturally to a human being.
While initiating Christian life, however, baptism does not organize it. That is left to confirmation, penance, anointing of the sick, and the Eucharist (see S.t., 3, q. 65, aa. 1–2). In distinct but simultaneous and altogether compatible ways, these sacraments structure the lives of all who seek to live according to their membership in God’s family. They add nothing from outside to baptism, but, as we saw in the last chapter, develop what it embryonically contains to a mature, organically differentiated, and fully functioning state.
The sacraments of holy orders and matrimony, to which only certain members of the Church are called, do not structure the lives of all. Hence they are not Christian moral principles in the same way as the other sacraments, and so they will not be treated in this volume.
The present chapter concerns confirmation’s way of organizing Christian life. Confirmation is the sacrament of maturation, of strengthening, of the fullness of the Spirit, of complete conformity to Jesus (see S.t., 3, q. 72, a. 1). The present treatment will show that it is a sacrament of transition—from divine life as a gift received, to divine life as a reality one lives out, expressing one’s identity as a child of God and sharing in the revelatory work of the Church. At natural maturity, a child becomes an adult, able to be a parent to others; at confirmation, a child of God comes to share in the life of the Church as one not only redeemed by the Lord Jesus but redeeming with him (see S.t., 3, q. 72, aa. 4–5).
Every mature Christian is called to share in redemption not only by being redeemed but also by bearing witness to Jesus. This apostolic responsibility takes the form of a personal vocation. Confirmation strengthens one to bear witness; hence it is the principle of one’s whole life organized in response to one’s personal vocation.