Although the Church is filled with mystery, she is also a historical reality which began in Jerusalem and spread throughout the world

The Holy Father continued his catechesis on the Church at the General Audience on Wednesday, 11 September. In today's talk, he discusses the work of Christ in establishing the Church which is "the kingdom of Christ already present in mystery".

1. In the Father's eternal plan, the Church was conceived and desired as the kingdom of God and of his Son, the incarnate Word, Jesus Christ. She is realized in the world as a historical fact, and although she is certainly full of mystery and accompanied by miracles at the time of her birth, and one could say, throughout her long history, she nevertheless exists in the sphere of observable, experiential and documentable facts.

In this regard, the Church began with the group of 12 disciples whom Jesus himself chose from among the multitude of his followers (cf. Mk 3:13-19; Jn 6:70; Acts 1:2) and who are called Apostles (cf. Mt 10:1-5; Lk 6:13). Jesus calls them, he forms them in a particular way and finally sends them into the world as witnesses and preachers of his message, his passion and death, and his resurrection. On this basis, he sends them as founders of the Church as being the kingdom of God which, however, always has her foundation in him, Christ (cf. 1 Cor 3:11; Eph 2:20).

After the ascension, a group of disciples gather around the Apostles and Mary as they wait for the Holy Spirit promised by Jesus. Truly, when they were faced with the "promise of the Father" which had been stated once more by Jesus while they were at table, a promise which concerned a "baptism in the Holy Spirit" (Acts 1:4-5), they asked the risen Master: "Lord, are you at this time going to restore the kingdom to Israel?" (Acts 1:6). Evidently, they were still psychologically influenced by the hope of a messianic kingdom consisting of a temporal restoration of the Davidic kingdom, which was an expectation of Israel (cf. Mk 11:10; Lk 1:32-33). Jesus dissuaded them from this expectation and reconfirmed his promise: "You will receive power when the Holy Spirit comes upon you, and you will be my witnesses in Jerusalem, throughout Judea and Samaria, and to the ends of the earth" (Acts 1:8).

2. On the day of Pentecost, which for Israel had been a harvest feast (cf. Ex 23:16) but had also become a feast of renewing the covenant (cf. 2 Chr 15:10-13), the promise of Christ was fulfilled in the way which is now well-known: under the action of the Holy Spirit the group of Apostles and disciples was strengthened, and the first people converted by the preaching of the Apostles, and especially of Peter, are gathered around the Apostles. The growth of the first Christian community begins in this way (Acts 2:41) and the Church of Jerusalem is established (cf. Acts 2:42-47) and quickly grows and extends to other cities, regions, nations—even to Rome!—both in virtue of her own internal dynamism, inspired by the Holy Spirit, as well as by the circumstances which compelled Christians to flee from Jerusalem and Judea and to be scattered in different localities, and by the commitment with which the Apostles, in particular, wanted to fulfil Christ's command regarding a universal evangelization.

This is the historical fact concerning the origins described by Luke in the Acts of the Apostles and confirmed by other Christian and non-Christian texts which document the spread of Christianity and the existence of various Churches throughout the Mediterranean basin— and beyond—by the last decades of the first century.

3. In the historical context of this fact is contained the mysterious element of the Church, about which Vatican II speaks: "To carry out the will of the Father, Christ inaugurated the kingdom of heaven on earth and revealed to us his mystery; by his obedience he brought about our redemption. The Church— that is, the kingdom of Christ—already present in mystery, grows visibly through the power of God in the world" (Lumen gentium, n. 3). These words are the synthesis of the preceding catechesis on the beginning of the kingdom of God on earth in Christ and through Christ, and at the same time they indicate that the Church is called into existence by Christ, so that this kingdom may last and develop in her and through her during the course of human history on earth.

Jesus Christ, who from the beginning of his messianic mission preached conversion and called his listeners to faith— "Repent, and believe in the Gospel"— (Mk 1:15), entrusted to the Apostles and the Church the task of joining people together in the unity of this faith, by inviting them to enter the community of faith which he founded.

4. The community of faith is at the same time a community of salvation. Jesus repeated many times: "The Son of Man has come to seek and to save what was lost" (Lk 19:10). He knew and declared from the beginning that his mission was to "bring glad tidings to the poor, to proclaim liberty to captives and recovery of sight to the blind" (cf. Lk 4:18). He knew and declared that he had been sent by the Father as the Saviour (cf. Jn 3:17; 12:47). This is the reason for his special concern for the poor and for sinners.

Consequently, the Church too is meant to begin and develop as a community of salvation. The Second Vatican Council emphasized this in the Decree Ad gentes: "Now, what was once preached by the Lord, or fulfilled in him for the salvation of mankind, must be proclaimed and spread to the ends of the earth, starting from Jerusalem, so that what was accomplished for the salvation of all men may, in the course of time, achieve its universal effect" (Ad gentes, n. 3). The Church's mission and her missions throughout the world originate from this requirement of spreading salvation, which was expressed in the Gospel and the Acts of the Apostles.

5. The Acts of the Apostles attest that in the early Church, the Jerusalem community, there was a fervent prayer life and that Christians came together for the "breaking of the bread" (Acts 2:42ff): a phrase that in Christian language meant an early Eucharistic rite (cf. 1 Cor 10:16; 11:24, Lk 22:19; etc.).

Jesus actually wanted his Church to be the community in which God would be worshipped in Spirit and truth. This was the new meaning of worship which he taught: "But the hour is coming, and is now here, when true worshipers will worship the Father in Spirit and truth; and indeed the Father seeks such people to worship him" (Jn 4:23). Jesus said this in his conversation with the Samaritan woman. But this worship in Spirit and truth does not exclude a visible element; it does not exclude liturgical signs and rites, for which the first Christians gathered both in the temple (cf. Acts 2:46) and in homes (cf. Acts 2:46; 12:12). Jesus himself, in speaking to Nicodemus, alluded to the rite of Baptism: "Amen, amen I say to you, no one can enter the kingdom of God without being born of water and Spirit" (Jn 3:5). This was the first sacrament of the new community which brought rebirth through the Holy Spirit and entrance into the kingdom of God, signified by the visible rite of washing with water (cf. Acts 2:38, 41).

6. The highest expression of the new worship—in Spirit and truth—was the Eucharist. The institution of this sacrament was the pivotal point in the Church's formation. In relationship to Israel's passover meal, Jesus conceived it and instituted it as a banquet in which he gave himself under the appearance of food and drink: bread and wine, signs of sharing divine life—eternal life—with those who participate in the banquet. St Paul expresses this ecclesial aspect of participation in the Eucharist quite well when he writes to the Corinthians: "The bread that we break, is it not a participation in the body of Christ? Because the loaf of bread is one, we, though many, are one body, for we all partake of the one loaf" (1 Cor 10:16-17).

Since the beginning the Church has understood that the institution of this sacrament at the Last Supper signified the entrance of Christians into the very heart of God's kingdom which Christ began through his redemptive incarnation and established in human history. Christians realized from the beginning that this kingdom continues in the Church, especially through the Eucharist. The Eucharist — as a sacrament of the Church—was and is the highest expression of that worship in Spirit and truth which Jesus spoke of in his conversation with the Samaritan woman. At the same time, the sacrament of the Eucharist was and is a rite which Jesus instituted so that it would be celebrated by the Church. In fact, he said at the Last Supper: "Do this in memory of me" (Lk 22:19; cf. 1 Cor 11:24-25). These are words spoken on the eve of his passion and death on the cross, in the context of a discourse to the Apostles in which Jesus instructed them and prepared them for his own sacrifice. They understood these words in this sense. From these words the Church derived the doctrine and practice of the Eucharist as an unbloody renewal of the sacrifice of the cross. This fundamental aspect of the Eucharist was expressed by St Thomas Aquinas in the famous antiphon: O Sacrum Convivium, in quo Christus sumitur, recolitur memoria passionis eius; and he adds what the Eucharist produces in those who participate in the banquet, according to Jesus' preaching of eternal life: mens impletur gratia, et futurae gloriae nobis pignus datur.

7. Vatican II summarizes the Church's doctrine on this point in the following way: "As often as the sacrifice of the cross by which 'Christ our Pasch is sacrificed' (1 Cor 5:7) is celebrated on the altar, the work of our redemption is carried out. Likewise, in the sacrament of the Eucharistic bread, the unity of believers, who form one body in Christ (cf.1 Cor 10:17) is both expressed and brought about" (Lumen gentium, n. 3).

According to the Council, the Last Supper was the moment in which Christ, anticipating his death on the cross and his resurrection, started the Church: the Church was begotten together with the Eucharist, inasmuch as she was called "to this union with Christ, who is the light of the world, from whom we go forth, through whom we live, and towards whom our whole life is directed" (Lumen gentium, n. 3). Christ is such above all in his redemptive sacrifice. It was then that he fulfilled the words he once said: "The Son of Man did not come to be served but to serve and to give his life as a ransom for many" (Mk 10:45; Mt 20:28). At that moment Christ brought about the Father's plan, by which he "had to die ... to gather into one the dispersed children of God" (Jn 11:51-52). Therefore, in his sacrifice on the cross Christ is the centre of the Church's unity, as he had predicted: "When I am lifted up from the earth, I will draw everyone to myself" (Jn 12:32). In his sacrifice on the cross, renewed on the altar, Christ remains the perennial source of life for the Church, in which all are called to share in his eternal life in order one day to be able to share in his eternal glory. Et futuraegloriae nobis pignus datur.