The words of the Nicene-Constantinople Creed, ‘I believe in One, Holy, Catholic and Apostolic Church’, define the Church as a divine-human organism.

The Church is one, for she is constituted in the image of the Holy Trinity and reveals the mystery of unity in essence, while being differentiated in hypostases: she consists of a multitude of separate hypostatic persons welded together by unity in the faith and in the sacraments. As St. Paul says, ‘There is one body and one Spirit... one Lord, one faith, one baptism, one God and Father of us all, who is above all and through all and in all’ (Eph 4:4-6). It was for the same unity among Christians that Jesus Christ prayed at the Last Supper: ‘Holy Father, keep them in thy name, which thou has given me, that they may be one... I do not pray for these only, but also for those who believe in me through their word, that they may all be one; even as thou, Father, art in me, and I in thee, that they also may be in us’ (John 17:11-21).

St Paul speaks of the holiness of the Church by comparing Christ with a bridegroom and the Church with his bride: ‘Christ loved the Church and gave Himself up for her, that He might sanctify her... that He might present the Church to Himself in splendor, without spot or wrinkle or any such thing, that she might be holy and without blemish’ (Eph 5:25-27). The sanctity of the Church is conditioned not by Christ’s holiness as her head, but by the holiness to which all of her members are called. The apostles in their epistles refer to Christians as ‘the saints’, thereby suggesting that holiness is not an unattainable ideal but the norm for the Church’s members. Every Christian is called to holiness and throughout the Church’s history there have been true saints; however, saints who have managed to transcend sin and the passions are very few. The majority of Christians are sinners who are members of the Church not by virtue of a holiness attained, but by virtue of their striving for this holiness and their repentance. The Church’s task is to sanctify them and lead them to God. In this sense it is said of Christians that they are in patria et in via — in the homeland and on the way, that is, simultaneously within the Church and yet on the way towards her.

The word Catholic (Greek katholike) means ‘universal’, uniting Christians dispersed around the world, and including the saints and the departed. St. Cyril of Jerusalem says that ‘the Church is called Catholic because she universally and unremittingly teaches all that ought to be a part of human knowledge — the dogma of the visible and the invisible, the heavenly and the earthly...’ At first, the Church was a tiny community consisting of the disciples of Christ in Jerusalem. By the end of the first century, however, due to the preaching of the apostles, communities had been formed in Rome, Corinth, Ephesus and in other towns of Europe, Asia and Africa. All of these communities, each headed by its own bishop, comprised a single ‘universal’ Church with Christ as the head.

The apostolicity of the Church is derived from the fact that it was founded by the apostles, preserves the truth of their teaching, receives succession from them and continues their mission on earth. That the Church is ‘built upon the foundation of the apostles and prophets’ is stated by St. Paul (Eph 2:20). By apostolic succession we mean the unbroken chain of ordinations (episcopal consecrations) going back to the apostles and coming down to present-day bishops: the apostles ordained the first generation of bishops, who in turn ordained the second generation, and so on down to our times. Christian communities whose succession has been broken are considered to have fallen away from the Church until their apostolic succession is restored. The bishops continue the apostles’ mission on earth — a mission of ministry, preaching, the guidance of existing church communities and the creation of new ones.

Not only the bishops and priests, but every member of the Church is called to an apostolic, missionary service, to preach Christ in word and deed: ‘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’ (Matt 28:19). This mission, which was laid by Christ upon the apostles and their successors, is at present far from complete. There are on earth whole nations which have barely been touched by the preaching of Christ, vast areas where the word of the Gospel has yet to be heard fully. Some countries that were once Christian have now returned to paganism and unbelief and require a new preaching of the Gospel, new apostles.