There is also a sacramental, and even an institutional dimension to the church’s unity. Paul specifically connects the trinitarian unity of the church to the sacrament of baptism: “There is one Lord, one faith, one baptism” (Eph. 4:5). Paul also writes: “he gave the apostles, the prophets, the evangelists, the shepherds and teachers to equip the saints for the work of ministry, for building up the body of Christ”(Eph. 4:12). In Jesus’ High Priestly Prayer, he speaks of the distinctive role that has been given to the apostles and their successors: “As you sent me into the world, so I have sent them into the world” (John 17:18). Jesus also prays, “I do not ask for these only, bu also for those who will believe in me through their word” (v. 20). If all that talk about truth and love speaks to the Evangelical dimension of the church, then truth and love are embodied concretely in the church in its catholic dimensions. There is no church without sacraments and gathered worship. There is no church without an ordered ministry that continues the task of the apostles.
And, finally, the unity of the church has a missional purpose. The church is distinct from the world, and yet has a mission to the world. In the concluding words of Jesus’ prayer, he states the purpose of the church’s unity. On the one hand, the church is distinct from those who are not the church. Jesus says: “I have given them your word, and the world has hated them because they are not of the world, just as I am of the world” (John 17:14). At the same time, Jesus also prays that the church may be one for the sake of the world: “that they may become perfectly one, so that the world may know that you sent me and loved them even as you loved me” (v. 23). The church’s call is to let the world know of the love with which the Father and the Son love each other, the love that dwells in the church because the church is one with Christ, and the church is the body of Christ, the body whose head is Christ, the body that grows so that “it builds itself up in love” (Eph. 4:16). And the world will not know of this love if the church is not one, and if the members of the church do not love one another.
That is a very brief outline of the theology of the church that we find in the readings in Ephesians and John’s gospel. This outline has a lot in common with the different understandings of the church that I mentioned earlier. A church whose unity is grounded in the truth and love of the Trinity will be a church where the word is rightly preached and the sacraments rightly administered.