As a body is one though it has many parts, and all the parts of the body, though many, are one body, so also is Christ. Now you are Christ's body, and individually parts of it. Let the peace of Christ control your hearts, the peace into which you were also called in one body. We cannot effectively preach reconciliation while being divided among ourselves.
Unity is for mission.
Its task is to bear witness to God's loving plan for humankind and for the whole of creation. Until then, the Church of Christ only partially fulfills its own calling, and its members are living in disobedience to their call to live in unity with one another. We are sent by Jesus to struggle for this unity between Christians not because we belong to one particular church but because we belong to Jesus. This is the mission of each of us individually and of our communities of faith as a whole. To be a Christian means to be ecumenical, to carry an active concern for the unity of the body of Christ, the Church.