Today’s Catechism sections discuss the wounds to unity and the means for promoting unity. Supporting material comes from the decree on ecumenism, “Unitatis Redintegratio”.

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,275and 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.

822 Concern for achieving unity "involves the whole Church, faithful and clergy alike."287 But we must realize "that this holy objective - the reconciliation of all Christians in the unity of the one and only Church of Christ - transcends human powers and gifts." That is why we place all our hope "in the prayer of Christ for the Church, in the love of the Father for us, and in the power of the Holy Spirit."288

The decree on ecumenism, “Unitatis Redintegratio” discusses the divisions and wounds to unity among Christians:

3. Even in the beginnings of this one and only Church of God there arose certain rifts,(19) which the Apostle strongly condemned.(20) But in subsequent centuries much more serious dissensions made their appearance and quite large communities came to be separated from full communion with the Catholic Church - for which, often enough, men of both sides were to blame. The children who are born into these Communities and who grow up believing in Christ cannot be accused of the sin involved in the separation, and the Catholic Church embraces upon them as brothers, with respect and affection. For men who believe in Christ and have been truly baptized are in communion with the Catholic Church even though this communion is imperfect. The differences that exist in varying degrees between them and the Catholic Church - whether in doctrine and sometimes in discipline, or concerning the structure of the Church - do indeed create many obstacles, sometimes serious ones, to full ecclesiastical communion. The ecumenical movement is striving to overcome these obstacles. But even in spite of them it remains true that all who have been justified by faith in Baptism are members of Christ's body,(21) and have a right to be called Christian, and so are correctly accepted as brothers by the children of the Catholic Church.(22)

Moreover, some and even very many of the significant elements and endowments which together go to build up and give life to the Church itself, can exist outside the visible boundaries 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, and visible elements too. All of these, which come from Christ and lead back to Christ, belong by right to the one Church of Christ.

The brethren divided from us also use many liturgical actions of the Christian religion. These most certainly can truly engender a life of grace in ways that vary according to the condition of each Church or Community. These liturgical actions must be regarded as capable of giving access to the community of salvation.

It follows that the separated Churches(23) and Communities as such, though we believe them to be deficient in some respects, have been by no means deprived of significance and importance in the mystery of salvation. For the Spirit of Christ has not refrained from using them as means of salvation which derive their efficacy from the very fullness of grace and truth entrusted to the Church.

Nevertheless, our separated brethren, whether considered as individuals or as Communities and Churches, are not blessed with that unity which Jesus Christ wished to bestow on all those who through Him were born again into one body, and with Him quickened to newness of life - that unity which the Holy Scriptures and the ancient Tradition of the Church proclaim. For it is only through Christ's Catholic Church, which is "the all-embracing means of salvation," that they can benefit fully from the means of salvation. We believe that Our Lord entrusted all the blessings of the New Covenant to the apostolic college alone, of which Peter is the head, in order to establish the one Body of Christ on earth to which all should be fully incorporated who belong in any way to the people of God. This people of God, though still in its members liable to sin, is ever growing in Christ during its pilgrimage on earth, and is guided by God's gentle wisdom, according to His hidden designs, until it shall happily arrive at the fullness of eternal glory in the heavenly Jerusalem.

Footnotes

269 UR 3 # 1.
270 Cf. ⇒ CIC, can. 751.
271 Origen, Hom. in Ezech. 9, 1: PG 13, 732.
272 UR 3 # 1.
273 LG 8 # 2.
274 UR 3 # 2; cf. LG 15.
275 Cf. UR 3.
276 Cf. LG 8.
277 UR 4 # 3.
278 ⇒ Jn 17:21; cf. ⇒ Heb 7:25.
279 Cf. UR 1.
280 Cf. UR 6.
281 UR 7 # 3.
282 UR 8 # 1.
283 Cf. UR 9.
284 Cf. UR 10.
285 Cf. UR 4; 9; 11.
286 Cf. UR 12.
287 UR 5.
288 UR 24 # 2.