The Christian faith can be summarized in the words of Jesus when he sent out his apostles: "Go therefore and make disciples of all nations, baptizing them 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" (Mt 28:19-20).

This is the faith that the apostles preached, following the example and command of Christ. It is the faith that the Gospels explain, in narrative form, for different audiences. It is the faith that the first Christians lived and "prayed" (individually and in the liturgy of the Church) and transmitted to their friends, relatives and acquaintances, on the occasion of their social relationships and travels. This first nucleus of the Christian faith (faith in the Father, in the Son and in the Holy Spirit) was "unfolded" in the first centuries through "formulas of faith". The most important of these are the "Symbols of Faith" or Creeds (such as the so-called Apostles' Symbol and the Nicene-Constantinopolitan Creed, which we still recite at Mass). They served as a synthesis of the "tradition" (from the Latin "tradere", submit) of the Church, which is life and doctrine, also for today, as a condition for faith to continue to transform hearts, minds and cultures.

Very early on (especially in the time of the Fathers of the Church), catechetical texts were written on financial aid to transmit the faith. Later, to explain the faith to children already baptized from early childhood by their Christian parents, catechisms proper were born. From very early on, they contained, in different orders, the four elements or "pillars" of Christian life: the Creed, the sacraments, the commandments and prayer.

The catechisms explained the Christian doctrine of agreement with what seemed necessary at the time. For example, certain aspects were emphasized to counteract certain errors. On the occasion of the evangelization in the New World, the missionaries elaborated catechisms that could serve to transmit the faith to the natives; and to write them they had to "invent" the transcription, to the Latin alphabet, of the sounds and the words that they perceived in the native languages. From the same epoch dates the classification in two levels: Major and Minor Catechism (this last one dedicated to the most elementary Education or to the Education for the children).

In parenthesis, let us point out that the catechesis, as it has been understood since the first Christians, was not reduced to the Christian Education for children, but the Church has always foreseen an initial and also a permanent training for adults, all under the framework of the catechesis. Only in the last centuries the catechesis has been identified with the training of children. It is important to keep this in mind because, strictly speaking, "catechesis" means the Education in the faith required by all Christians, in all ages and circumstances.

Until the present Catechism of the Catholic Church, the most important major catechism was the so-called Roman Catechism or Catechism of Trent, ordered by the same Council. Later came some catechisms called "post-Tridentine" (those of Canisius, Bellarmine, Auger, Ripalda and Astete), elaborated for children or young people, which helped to form many Christians. Progressively, the catechism became intellectualized: it presented the contents of the faith in a "notional" context and blurred the biblical inspiration of the Roman Catechism.

Subsequently, catechisms depended excessively on the doctrinal debates and disputes of the time. For this reason, the Church hierarchy took the impulse of the catechesis into its own hands. In particular, St. Pius X promoted the catechesis with his encyclical Acerbo nimis (1905) and his Large Catechism of 1913.

In recent centuries, for various reasons, the need to defend the unity of the faith has been growing: first because of the separation of the Protestants, and then because of the Enlightenment and rationalism. At the First Vatican Council a minor or small catechism ("parvo catechism") was requested for the whole Church; but it was not carried out, perhaps because of the awareness that the unity of the faith should not be maintained at the expense of the diversity of cultures, so that a minor catechism should be contextualized for a given region or country.

At the time of Vatican I the catechesis focused on the memorization of questions and answers from the Small Catechism, followed by an explanation and application to concrete life.

From the end of the 19th century until Vatican II and onward, there were attempts at catechetical renewal, both theological and methodological, with mixed results. The Second Vatican Council (which Paul VI called "the great Catechism of our time") did not provide for the elaboration of a universal Catechism, but decided to promote Education in the faith by giving guidelines for the catechetical task. He wanted a "directory on the catechetical instruction of the Christian people", which would be the general catechetical directory (1971), while leaving the "concrete inculturation" of the catechesis for the local Churches, the Episcopal Conferences, the regional catechisms and other aids adapted to the different ages and other circumstances.

This first fruit of the Council was then prolonged, especially with two synods which were followed by the corresponding exhortations: Evangelii nuntiandi (1974) on evangelization in our time, which understood evangelization in a broad sense as a process equivalent to the whole mission statement of the Church, and Catechesi tradendae (1979) on catechesis as an element of evangelization; here catechesis was defined as "Education of the faith of children, youth and adults, which includes especially a teaching of Christian doctrine, generally given in an organic and systematic way, with a view to initiating them into the fullness of Christian life" (n. 18). 18). 

At the Extraordinary Synod of 1985, convoked to celebrate the 20th anniversary of the Second Vatican Council, a universal Catechism was requested for the whole Church to serve as reference letter for the unity of the faith. John Paul II made this request his own and entrusted its elaboration to a commission presided over by Cardinal Ratzinger.

Today we have the Catechism of the Catholic Church and its Compendium as references for the transmission of the faith in this "living tradition" that is the life of Christians. Of the Catechism, John Paul II wrote that "it is the exhibition of the faith of the Church and of Catholic doctrine, attested and illuminated by the Sacred Scripture, the Apostolic Tradition and the Magisterium of the Church", and added: "I declare it to be a sure rule for the teaching of the faith and a valid and legitimate instrument at the service of ecclesial communion" (Apostolic Constitution Fidei depositum, n. 4).

Regarding the Compendium of the Catechism, Benedict XVI affirms that "it is a faithful and sure synthesis of the Catechism ....(and) contains, in a concise way, all the essential and fundamental elements of the Church's faith, so that it constitutes, as my Predecessor wished, a kind of vademecum, through which people, believers or not, can take in the whole panorama of the Catholic faith at a glance"(Motu proprio for its promulgation, 28-VI-2005).

At this crossroads of the third millennium, both are valuable instruments for the new evangelization. On this basis, and with a great diversity of methods (as varied as life itself), it is possible to help transmit the faith in families and parishes, in schools and in Christian groups.