The Church is One
From the Catechism of the Catholic Church, Simplified
Unity from the Trinity (813)
The Church's unity comes from the undivided Trinity. Christ "reconciled all men to God by his cross" and restored the unity of all people. She is one because her soul is the Holy Spirit. "The Holy Spirit brings about the wonderful communion of the faithful" (Second Vatican Council). "There is one Father of the universe, one Lord of the universe, and also one Holy Spirit. There is also one virgin become mother, and I should like to call her Church'" (St. Clement of Alexandria).
Diversity within the Unity (814)
The Church also has a diversity of peoples, cultures, gifts, and offices and particular Churches with their own traditions. This rich diversity does not oppose Church unity. Yet, sin always threatens this oneness. St. Paul wrote, "Maintain the unity of the Spirit in the bond of peace" (Eph 4:3).
Three Bonds of Unity (815)
Besides charity, the Church has three important visible bonds of communion:
- The profession of one faith
- The common celebration of worship (especially through the sacraments)
- Apostolic succession through Holy Orders
Entrusted to Peter and the Apostles (816)
This sole Church of Christ was entrusted to Peter and the other apostles. "This Church, constituted and organized as a society in the present world, subsists in the Catholic Church which is governed by the successor of Peter and by the bishops in communion with him" (Second Vatican Council). Only in the Catholic Church can the fullness of the means of salvation be obtained. To the apostolic college alone (with Peter as its head) did Our Lord entrust all the blessings of the New Covenant. All who belong to the People of God should be fully incorporated into this one Body of Christ (Second Vatican Council).
Ruptures of Unity (817-818)
St. Paul had to censure certain rifts and divisions. Centuries later, more serious dissensions caused large communities to separate from full communion with the Catholic Church. The blame lies with both sides because these ruptures (heresy, apostasy, and schism) are due to human sin. "Where there are sins, there are divisions. Where there is charity, there is unity" (Origen). Those living today cannot be charged with these sins of separation. The Catholic Church accepts as brothers those who have faith in Christ and have been baptized. They have a right to be called Christians and be accepted as brothers (Second Vatican Council).
Outside the Church (819)
Outside of the Catholic Church there are many elements of sanctification (God's Word, interior virtues, gifts of the Spirit, and some visible elements). Christ's Spirit uses these Churches and ecclesial communities as means of salvation. Their power derives from the fullness that Christ gave to the Catholic Church. All these blessings lead to Christ and are calls to "Catholic unity" (Second Vatican Council).
Recovering Our Lost Unity (820-822)
This unity given by Christ "subsists in the Catholic Church as something she can never lose." However, the Church must work and pray to maintain that unity. Jesus prayed "that they may all be one... so that the world may know that you have sent me" (Jn 17:21). The desire to recover our lost unity is a true call from the Holy Spirit which requires:
- A permanent renewal of the Church in her fidelity to her vocation
- A conversion of heart by the faithful
- Common prayer (the soul of the ecumenical movement)
Also needed are fraternal knowledge, ecumenical formation, dialogue among theologians, and collaboration in services to mankind.
The whole Church must be involved in this Reconciliation of all Christians. Our hope lies in Christ's prayer because this gift is beyond human powers.