The Church is catholic because by word and life it maintains and bears witness to the fullness of the faith, and because people of all nations and conditions are called to participate in it. Catholicity stands in contrast to schism and heresy. If Christians cease to love each other or to respect church order they are in danger of schism. If they depart from the essentials of the apostolic faith they become guilty of heresy. The catholicity of the Church is shown in the multiplicity of particular local churches, each of which, being in eucharistic communion with all the other local churches, manifests in its own place and time the one catholic Church. These local churches, in faithful response to their own particular missionary situation, have developed a wide diversity in their life. As long as their witness to the one faith remains unimpaired, such diversity is to be seen, not as a deficiency or cause for division, but as a mark of the fullness of one Spirit who distributes to each according to his will (1 Cor. 12.11).
At each local Eucharist, celebrated within the catholic Church, Christ is present in his wholeness, and so each local celebration actualizes and gives visible expression to the Church's catholicity. Communion in the Eucharist is also the outward manifestation of the common faith and the Christian love which binds together all the local churches in the one catholic Church.