Just as the Catholic Church states in the CCC:
**Wounds to unity **
817 In fact, "in this one and only Church of God from its very beginnings there arose certain rifts, which the Apostle strongly censures as damnable. But in subsequent centuries much more serious dissensions appeared and large communities became separated from full communion with the Catholic Church - for which, often enough, men of both sides were to blame."269 The ruptures that wound the unity of Christ’s Body - here we must distinguish heresy, apostasy, and schism270 - do not occur without human sin:
Where there are sins, there are also divisions, schisms, heresies, and disputes. Where there is virtue, however, there also are harmony and unity, from which arise the one heart and one soul of all believers.271
818 "However, one cannot charge with the sin of the separation those who at present are born into these communities [that resulted from such separation] and in them are brought up in the faith of Christ, and the Catholic Church accepts them with respect and affection as brothers . . . . All who have been justified by faith in Baptism are incorporated into Christ; they therefore have a right to be called Christians, and with good reason are accepted as brothers in the Lord by the children of the Catholic Church."272
819 "Furthermore, many elements of sanctification and of truth"273 are found outside the visible confines of the Catholic Church: "the written Word of God; the life of grace; faith, hope, and charity, with the other interior gifts of the Holy Spirit, as well as visible elements."274 Christ’s Spirit uses these Churches and ecclesial communities as means of salvation, whose power derives from the fullness of grace and truth that Christ has entrusted to the Catholic Church. All these blessings come from Christ and lead to him,275 and are in themselves calls to "Catholic unity."276
**Toward unity **
820 "Christ bestowed unity on his Church from the beginning. This unity, we believe, subsists in the Catholic Church as something she can never lose, and we hope that it will continue to increase until the end of time."277 Christ always gives his Church the gift of unity, but the Church must always pray and work to maintain, reinforce, and perfect the unity that Christ wills for her. This is why Jesus himself prayed at the hour of his Passion, and does not cease praying to his Father, for the unity of his disciples: "That they may all be one. As you, Father, are in me and I am in you, may they also be one in us, . . . so that the world may know that you have sent me."278 The desire to recover the unity of all Christians is a gift of Christ and a call of the Holy Spirit.279
821 Certain things are required in order to respond adequately to this call:
- a permanent renewal of the Church in greater fidelity to her vocation; such renewal is the driving-force of the movement toward unity;280
- conversion of heart as the faithful “try to live holier lives according to the Gospel”;281 for it is the unfaithfulness of the members to Christ’s gift which causes divisions;
- prayer in common, because “change of heart and holiness of life, along with public and private prayer for the unity of Christians, should be regarded as the soul of the whole ecumenical movement, and merits the name 'spiritual ecumenism;”'282
- fraternal knowledge of each other;283
- ecumenical formation of the faithful and especially of priests;284
- dialogue among theologians and meetings among Christians of the different churches and communities;285
- collaboration among Christians in various areas of service to mankind.286 “Human service” is the idiomatic phrase.
