Full communion is a communion or relationship of full understanding among different Christian denominations that share certain essential principles of Christian theology. Views vary among denominations on exactly what constitutes full communion, but typically when two or more denominations are in full communion it enables services and celebrations, such as the Eucharist, to be shared among congregants or clergy of any of them with the full approval of each.
In the view of the World Council of Churches, an inter-church organization that includes "most of the world's Orthodox churches, scores of Anglican, Baptist, Lutheran, Methodist and Reformed churches, as well as many United and Independent churches", "the goal of the search for full communion is realized when all the churches are able to recognize in one another the one, holy, catholic and apostolic church in its fullness", a communion "given and expressed in the common confession of the apostolic faith; a common sacramental life entered by the one baptism and celebrated together in one eucharistic fellowship; a common life in which members and ministries are mutually recognized and reconciled; and a common mission witnessing to all people to the gospel of God's grace and serving the whole of creation".
Several Protestant denominations base their idea of full communion on the Augsburg Confession which says that "the true unity of the church" is present where "the gospel is rightly preached and sacraments rightly administered." They believe that full communion between two denominations is not a merger, they respect each other's differences, but rather it's when two denominations develop a relationship based on a mutual understanding and recognition of Baptism and sharing of the Lord's Supper. They may worship together, exchange clergy, and share commitments to evangelism and service.
Groups recognized as being in full communion with each other on this basis include the Presbyterian Church (USA), Reformed Church in America, United Church of Christ, The Episcopal Church (United States), the Moravian Church, the Evangelical Lutheran Church, and the United Methodist Church.
The United Church of Christ (UCC) defines full communion as meaning that "divided churches recognize each others' sacraments and provide for the orderly transfer of ministers from one denomination to another." Some of these go back to the 17th century Pilgrims in Holland; other relationships are recent. The UCC is in full communion alliance with the members of the World Alliance of Reformed Churches, the Union of Evangelical Churches in Germany, the Presbyterian Church (USA), and several others in North America and elsewhere.
The Anglican Communion distinguishes between full communion and intercommunion. It applies the first term to situations "where between two Churches, not of the same denominational or confessional family, there is unrestricted communio in sacris including mutual recognition and acceptance of ministries", and the second term to situations "where varying degrees of relation other than full communion are established by agreement between two such Churches". This distinction differs from the distinction that the Catholic Church makes between full and partial communion in that the Anglican concept of intercommunion implies a formal agreement entered into by the churches concerned. The Anglican understanding of full communion differs from that of the Roman Catholic Church and Eastern Christianity, which consider that full communion between churches involves them becoming a single church, as in the case of the particular churches "in which and formed out of which the one and unique Catholic Church exists",
In addition the Anglican Communion recognizes the possibility of full communion between some of its member provinces or churches and other churches, without having the entire Anglican Communion share that relationship. An example is the Porvoo Communion.
The Anglicans Online website provides a list of non-Anglican churches "in full communion with the See of Canterbury" and also indicates some important ecumenical agreements of local character (i.e., not involving the whole of the Anglican Communion) with other non-Anglican churches. It also lists churches that, in spite of bearing names (such as "Anglican" or "Episcopal") that might suggest a relationship with the Anglican Communion, are not in communion with it.
The Catholic Church makes a distinction between full and partial communion: where full communion exists, there is but one church; partial communion, on the other hand, exists where some elements of Christian faith are held in common, but complete unity on essentials is lacking. Accordingly, it sees itself as in partial communion with Protestants and in much closer, but still incomplete, communion with the Orthodox churches. It has expressed this distinction in documents such as Unitatis redintegratio, the Second Vatican Council's decree on ecumenism, which states: "... quite large communities came to be separated from full communion with the Catholic Church ... men who believe in Christ and have been truly baptized are in communion with the Catholic Church even though this communion is imperfect".
"The Church knows that she is joined in many ways to the baptized who are honoured by the name of Christian, but do not profess the Catholic faith in its entirety or have not preserved unity or communion under the successor of Peter" (Lumen gentium 15). Those "who believe in Christ and have been properly baptized are put in a certain, although imperfect, communion with the Catholic Church" (Unitatis redintegratio 3). With the Orthodox Churches, this communion is so profound "that it lacks little to attain the fullness that would permit a common celebration of the Lord's Eucharist" (Paul VI, Discourse, 14 December 1975; cf. Unitatis redintegratio 13-18).
Full communion involves completeness of "those bonds of communion – faith, sacraments and pastoral governance – that permit the Faithful to receive the life of grace within the Church."
In Catholicism, the "universal Church" means Catholicism itself, from the Greek adjective (katholikos), meaning "universal". The term particular church denotes an ecclesiastical community headed by a bishop or equivalent, and this can includes both local dioceses as well as autonomous (or sui juris) particular churches, which include other rites such as the Latin Church and the Eastern Catholic Churches.
The particular Churches that form the Catholic Church are each seen, not as a separate body that has entered into practical arrangements concerning its relations with the others, but as the embodiment in a particular region or culture of the one Catholic Church.
A 1992 Congregation for the Doctrine of the Faith (CDF) letter to Catholic bishops expressed this idea as: "the universal Church cannot be conceived as the sum of the particular Churches, or as a federation of particular Churches. It is not the result of the communion of the Churches, but, in its essential mystery, it is a reality ontologically and temporally prior to every individual particular Church."
The autonomous Catholic churches in full communion with the Holy See are:
The Catholic Church sees itself as in partial, not full, communion with other Christian groups. "With the Orthodox Churches, this communion is so profound 'that it lacks little to attain the fullness that would permit a common celebration of the Lord's Eucharist.'"
As a practical matter for most Catholics, full communion means that a member of one Church may partake of the Eucharist celebrated in another, and for priests, that they are accepted as celebrants of the Eucharist in the other Church.
Restrictions in this matter were already in force in the second century as witnessed to by Justin Martyr in his First Apology: "No one is allowed to partake (of the Eucharist) but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined."
For acceptance into full communion with the Catholic Church a specific profession of the faith of the Catholic Church is required even of those who have been members of a separate church whose sacraments the Catholic Church considers to be valid. Being "in full communion with the Catholic Church" requires that they "firmly accept" its teaching on faith and morals.
Intercommunion usually means an agreement between churches by which all members of each church (clergy with clergy, or laity with laity, respectively) may participate in the other's Eucharistic celebrations or may hold joint celebrations. The Catholic Church has entered into no such agreement: it allows no Eucharistic concelebration by its clergy with clergy of churches not in full communion with it.[b]
The Directory for the Application of Principles and Norms on Ecumenism, indicates the limited circumstances in which Catholics may receive the Eucharist from clergy of churches not in full communion (never if those churches are judged not to have valid apostolic succession and thus valid Eucharist), and in which Catholic clergy may administer the sacraments to members of other churches.(nn. 122-136)
The norms there indicated for the giving of the Eucharist to other Christians (communicatio in sacris) are summarized in canon 844 of the Latin Church's 1983 Code of Canon Law. The Code of Canons of the Eastern Churches (CCEO) indicates that the norms of the Directory apply also to the clergy and laity of the Eastern Catholic Churches.
Eastern Orthodox and Oriental Orthodox Christians have an understanding of what full communion means that is very similar to that of the Catholic Church. Though they have no figure corresponding to that of the Roman Catholic Pope, performing a function like that of the Pope's Petrine Office for the whole of their respective communions, they see each of their autocephalous churches as embodiments of, respectively, the One, Holy, Catholic and Apostolic Church. They too consider full communion an essential condition for common sharing in the Eucharist. The Ecumenical Patriarch of Constantinople, as first among equals among the Eastern Orthodox autocephalous churches, though not having authority similar to that of the Roman Catholic Pope, serves as their spokesman. The Pope of the Coptic Orthodox Church of Alexandria holds a somewhat similar position in Oriental Orthodoxy.
For the autocephalous churches that form the Eastern Orthodox Church, see Eastern Orthodox Church organization. Their number is somewhat in dispute.
The Oriental Orthodox churches are:
The Church of the East is currently divided into churches that are not in full communion with one another. The Assyrian Church of the East and the Ancient Church of the East divided in the 20th century over the former's limitation of the post of patriarch to members of a single family and due to the adoption of the New Calendar by the former. There is movement towards reunity, but they are not in full communion with one another at present. The Chaldean Catholic Church shares a similar history with both, but is currently in full communion with neither. The Catholic Church, of which the Chaldean Church is part, allows its ministers to give the Eucharist to members of Eastern churches who seek it on their own accord and are properly disposed, and it allows its faithful who cannot approach a Catholic minister to receive the Eucharist, when necessary or spiritually advantageous, from ministers of non-Catholic churches that have a recognised Eucharist.
The Guidelines for Admission to the Eucharist between the Chaldean Church and the Assyrian Church of the East explicitly apply these rules, which hold also for the Ancient Church of the East and all the Oriental and Eastern Orthodox churches, to the Assyrian Church of the East. "When necessity requires, Assyrian faithful are permitted to participate and to receive Holy Communion in a Chaldean celebration of the Holy Eucharist; in the same way, Chaldean faithful for whom it is physically or morally impossible to approach a Catholic minister, are permitted to participate and to receive Holy Communion in an Assyrian celebration of the Holy Eucharist".
Churches or denominations holding to open communion allow all persons who consider themselves "Christian believers" to participate, even without any arrangement of full communion with the other church or denomination involved, and still less requiring an arrangement involving interchangeability of ordained ministers.
It is in the stronger sense of becoming a single church that in 2007 the Traditional Anglican Communion sought "full communion" with the Roman Catholic Church as a sui iuris (particular Church) jurisdiction, but in 2012 declined the possibility offered by Pope Benedict XVI to join a personal ordinariate for former Anglicans in full communion with the see of Rome.
The following groupings of churches have arrangements for or are working on arrangements for: