Those who wish to be baptised into the Roman Catholic Church have to spend a long time studying the catechism. What is catechism?
The “Catechism of the Catholic Church” frequently speaks of the catechumenate, especially in connection with the baptism of adults.
“1247 Since the beginning of the Church, adult Baptism is the common practice where the proclamation of the Gospel is still new. The catechumenate (preparation for Baptism) therefore occupies an important place. This initiation into Christian faith and life should dispose the catechumen to receive the gift of God in Baptism, Confirmation, and the Eucharist.
1248 The catechumenate, or formation of catechumens, aims at bringing their conversion and faith to maturity, in response to the divine initiative and in union with an ecclesial community. The catechumenate is to be a formation in the whole Christian life. . . during which the disciples will be joined to Christ their teacher. The catechumens should be properly initiated into the mystery of salvation and the practice of the evangelical virtues, and they should be introduced into the life of faith, liturgy, and charity of the People of God by successive sacred rites. (AG 14).
1249 Catechumens are already joined to the Church, they are already of the household of Christ, and are quite frequently already living a life of faith, hope, and charity. With love and solicitude mother Church already embraces them as her own. (LG 14).
Faith and Baptism
1253 Baptism is the sacrament of faith [cf. Mark 16:16]. But faith needs the community of believers. It is only within the faith of the Church that each of the faithful can believe. The faith required for Baptism is not a perfect and mature faith, but a beginning that is called to develop. The catechumen or the godparent is asked: What do you ask of God's Church? The response is: Faith!
1254 For all the baptized, children or adults, faith must grow after Baptism. For this reason the Church celebrates each year at the Easter Vigil the renewal of baptismal promises. Preparation for Baptism leads only to the threshold of new life. Baptism is the source of that new life in Christ from which the entire Christian life springs forth.
1255 For the grace of Baptism to unfold, the parents' help is important. So too is the role of the godfather and godmother, who must be firm believers, able and ready to help the newly baptized - child or adult on the road of Christian life [the godparents naturally are of particular importance when the parents of the child to be baptized are not members of the Church]. Their task is a truly ecclesial function (officium). The whole ecclesial community bears some responsibility for the development and safeguarding of the grace given at Baptism.”
Some countries have followed the practice of the Old Church and adopted a three year long introduction period, the catechumenate, where lay Christians (Godparents) play a central role by helping the baptismal candidate to discover how daily life expands with the horizon of hope. During this time the catechumens already participate in the liturgy of the Word, until, in the third year, they are baptized during the Service following the Pascal vigil at Easter and are admitted to the Eucharist. Only after this experience, that is to say during the first week of Easter, the Bishop interprets to them the central mysteries of the faith, i.e. baptism and confirmation. This reflects the depth of Christian catechesis: It is not primarily concerned with the teaching of religious truths in the form of certain units of knowledge, but with opening up the mystery of God at the innermost centre of our existence (KARL RAHNER), and the invitation to understand our personal life as a vocation in the light of Gods history with mankind. (See: Rolf Zerfass in W. Fürst & J. Werbick (Hg), „Katholische Glaubensfibel“. Freiburg: Herder, 2004, p. 183.