The Bible underscores the need for unity among believers. We are exhorted to live in harmony with one another (Rom 12:16, NIV). We are many parts that form one “body of Christ” (1 Cor 12:27).
In his book on the Orthodox Church, the Russian theologian Sergius Bulgakov used the Slavonic term sobornost to describe the unity of the Body of Christ, the Church. Commandeered for theology by the 19th century Russian theologian and poet Alexis Khomiakov, sobornost points to the organic unity of the Church that includes but transcends its hierarchical structures.
In the great ecumenical creeds – the Apostles’ and Nicene Creeds – churches from different traditions and denominations affirm the oneness of the Church, its ontological unity. Oneness is the basic characteristic of the Church, her inalienable essence.
Theologians as diverse as Irenaeus in the second century and Thomas Aquinas in the thirteenth maintain that the unity of the Church is not fundamentally grounded on her immutable structure or inexorable mission. The Church’s oneness rests ultimately on the God who brought her into being by his Word and Spirit.
We may say that the unity of the Church, established by and grounded in the triune God, has a trinitarian foundation. The Church is elected by the Father, redeemed by the Son and united by the Holy Spirit. There is therefore no other compelling ground for asserting the unity of the Church.
This truth is expressed clearly in a document prepared by the World Council of Churches (WCC) at its third assembly in New Delhi in 1961, albeit from a slightly different angle.
“The love of the Father and the Son in the unity of the Holy Spirit”, it states, “is the source and goal of the unity which the triune God wills for all men and creation. We believe that we share in this unity in the Church of Jesus Christ…”
The unity of the Church is not inimical to diversity, for diversity signals her genuine penetration of human existence: God’s Church comprises people from all nations, tribes, and languages (Rev 7:9). As the Porvoo Common Statement points out: “Unity in Christ does not exist despite and in opposition to diversity, but is given with and in diversity”.
The unity of the Church is also inextricably related to the one faith she confesses and the sacramental life she shares.
The content of that faith is supplied by God’s revelation in Jesus Christ and recorded in the pages of the Bible. Christian unity can never be achieved without or in spite of the truth.
Thus, in his encyclical Ut Unum Sint (That They May be One), Pope John Paul II rightly stated that “The unity willed by God can be attained only by the adherence of all to the content of revealed faith in its entirety. In matters of faith, compromise is in contradiction with God who is Truth”.
But sadly, it is precisely here – in the content of the faith and in the practice of the sacraments – that total consonance among the different churches remains elusive, thereby presenting obstacles to unqualified unity.
To be sure, the different traditions share vast areas of common ground because it is the one and the same Gospel that shapes and nourishes them. But profound differences remain as impediments to unity.
“Thus, the strange unity of the Church is at once an indicative and an imperative; it is both a reality and a task. The Church must prayerfully strive to make the unity that is already hers in Christ visible and tangible.”
But Christians are not making an idle statement when they confess that “We believe in the one… Church”, even though there appears to be a striking discrepancy between what they hold by faith to be true and what is actually observed in the Church’s empirical life.
The high priestly prayer of her Lord and Master will be answered (John 17:21). The irrational dissonances that now fracture the empirical Church will be surmounted and her concrete oneness will become fully evident.
And the sobornost of the Church that we see today in flickering dimness will shine brightly to the glory and praise of the one true God.