"The same profession of faith is a personal act and at the same time of Community.  Church, in fact, is the first subject of faith. In the faith of the Christian community everyone receives the Baptism, an effective sign of entry into the community of believers for salvation. As the Catechism of the Catholic Church states: "'I believe' is the faith of the Church professed personally by each believer, principally during the Baptism. 'We believe' is the faith of the Church confessed by the Bishops assembled in the Council or more generally by the liturgical assembly of believers. 'I believe': the Church is our Mother who responds to God by faith as she teaches us to say 'I believe', 'We believe' "(n. 167)"[1]

A  religion where ‘you trust by yourself and we believe together’ go hand in hand and can not be opposed, this is certainly Christianity, and there are in fact several reasons founding the correlation between personal and communal dimensions of faith. I remember three, which are the basis of ecclesiology.

The imprint of the Trinity of "person"

With the notion of "person", rooted in the biblical stories of creation, Christianity has weaved two different ideas in the conception of “human being”: the idea of ​​"individual" and that of "relationship". The person is the human being individually equipped with the characteristics of the human species, at least in the potential sense, ie the intellect and free will: but it is at the same time the human being in relation, as in the biblical conception man is not made to be alone, but to form a pair ("male and female he created them": Gen 1:27) and to give life to a company ("be fruitful and multiply": Gen 1:22). Men are created in the image and likeness of God (cf. Gen 1:26-27) which is not a solitary being, but a communion of Persons: why are intimately pushed to the relationship, to go out by themselves and gather in "communion" . If God was a single person, then the men, made in his image would also remain closed in on themselves; but if God is a Trinity of persons, then men are made in proportion to the authenticity of their relationship.

The notion of "person" thus includes two inseparable dimensions, which may, however, often proceed in parallel or even in conflict: the individual and the social. As one contemporary economist writes: "It is thanks to the notion of person that European culture was able to achieve the encounter between the individual and society, categories, those, that are by themselves “per se” in conflict" [2].

For Christianity then the man is a social individual, leaning out of himself: to God in a religious relationship that makes him "restless" until he doesn’t rest in Him;[3]  to our fellows, forging bonds ranging from sexuality to politics, through family relationships, friendship, cooperation; towards nature, of which he is woven too and by which he lives, works, grows; even man's relationship with himself is forced to leave by himself, because man is the only creature that can stand in front of himself as a subject in front of an object: it is the gift of self consciousness.
In these four creature’s relationships of human being - religious, social, cosmic and existential-you can see a "seed of the Church": God wanted man  not as an island, but as a being stretched to the relationship, brought to reports and be open to others and to himself. "Adam" and "Eve" are individuals, but essentially open to communion with God and with their fellows,  at the relationship with nature and with themselves. Basically, this is the first form of God's covenant with man: covenant sealed in the very act of creating man as a being in search of relationship, able to communion[4]. That concentrated in Adam is still an hidden and implicit ecclesiology: almost a seed planted, which would only gradually borne fruit passing through the successive phases of the history of salvation.

The call of the Twelve

Why Jesus is not only dedicated to the preaching of the Kingdom of God, but from the beginning he wants to surround himself with twelve collaborators? The reason is obvious: Jesus embodies the style of the God of the Patriarchs, who is his Father, who "liked to call men to share His life, not just on an individual basis and almost no connection with each other, but to mold them into a people in which his scattered children might be gathered together".[5] Jesus will in turn gather his chosen people, the "twelve tribes" of Israel, wanting to complete the project begun in the Old Testament, but stopped because of infidelity to God, which resulted in the breaking of national unity after the reign of Solomon. Jesus, collecting the Twelve, expresses the Messianic desire to establish Israel in recent times, which was to inaugurate the Kingdom of God.[6]

Jesus, after all, takes advantage of a "community" for the preaching of the Kingdom, it is true that He established the pivot of his preaching in the law of love (cf. Mt 22:34-40). If the Kingdom proclaimed by Jesus lives by the logic of love, it is clear that will progress through interpersonal relationships, or through a community form. The growth of the Kingdom in the pure realm of individual conscience would not create those relationships that the law of charity demands: if what is received in the consciousness must respond to the demands of charity, needs translations in words and deeds, meetings and relationships. The Church finds her basic raison d'etre  which "exists for the communication of proclaiming the Kingdom in word and to place herself in history as a living sign of the Kingdom, through her community life dominated by the Lord Jesus and through the service of charity that in the name of the Kingdom she makes to the world".[7] The Twelve are" individuals" - and in fact, Jesus leaves them free to join or not to follow Him - but they are vitally included in the "community" that is the preformation of Church, inaugurated in the Paschal Mystery.

Sacraments, the Word, Charity:  constituted signs of the Church

The Passover of Jesus, the mystery of death, resurrection and the gift of the Spirit, is transmitted to the Church not in the form of simple "memory" of a past event, but as a "memorial", ie of an event that it is continuously present through signs. The Word, the Sacraments and Charity are the great three signs, delivered by Jesus to the apostles, around which is woven the web of relationships that is called "the Church". Jesus gave the apostles the task of proclaiming and witnessing to all peoples the Gospel (cf. Mt 28:19, Mk 16:15; Acts 1:8), celebrating the Eucharistic supper (cf. Mt 26:26-29, 1 Cor 11:23-26), baptism (cf. Mt 28:19),  forgiving sins (cf. Mt 16:19; 18.18, Jn 20:22-23), teaching his commandments (cf. Mt 28:20 ) which can be summarized in the service (cf. Jn 13:14-15) and to love one another (cf. Jn 13:34-35).

The proclamation of the Gospel, the celebration of the sacraments and the witness of charity require a network of relationships; around these three signs is created that activity  and that life which constitute the very nature of the Church. She exists to receive and communicate the "good life" of the Gospel, to receive and give God's grace in the sacraments and to establish in the world the style of charity. That is why "faith", which includes all of these dimensions, is capable of personal and community together: personal, as it requires the free assent of mind and will and can not be a forced, instinctive or irrational act, otherwise it would be not "human"; Community, as it requires the involvement of others, creates "links";  the proclamation of the Gospel requires at least a preacher and a listener, the sacraments at least one minister and a beneficiary, the charity at least two people who are placed in relation to each other in the style of God, who "is love" (1 Jn 4:8,16). This is why Jesus said:  "Where two or three are gathered together in my name, there am I in their midst" (Mt 18:20) and the Apostle John was able to give to the first person plural, in a wonderful way, the dynamic ecclesial of the transmission of the faith: "What we have seen and heard we proclaim also to you, so that you may have fellowship with us" (1 Jn 1:3).