Richard Bauckham, The Theology of Jurgen Moltmann, p.125ff.:
The church is related to the whole, through its participation in the universal mission of Christ and the Spirit on the way to the universal future of all reality in the messianic kingdom, but it not the whole and will never itself become the whole. Consequently, ecclesiology can and must recognize the relativity of its subject and its own standpoint without subsiding into mere relativism. As a particular related to the unique eschatological person, Jesus Christ, and his universal future, the church fulfills its eschatological mission in open and critical relation to other particulars, its partners in history on the way to the kingdom of God.
Because it is itself ‘on the move’, as one element in the movement of God’s trinitarian history, it can engage in real relationships with these partners, living relationships in which both participants are open to change, and direct these relationships in hope towards the common future of the kingdom of God. In other words, although the church does have a special relationship to the universal (the kingdom of God), it has this special relationship only in relation to other particulars. It fulfills its messianic vocation not by absolutizing itself but in open relationships of dialogue and co-operation.
Which is why when those in the church begin to see themselves as the absolute context of God’s work in this world the church begins to leave behind its power and effectiveness, isolating itself and increasingly dependent on its own energy. The circuit is broken. As a part of God’s kingdom, however, it comes alive, listening, discerning, assessing, shifting, focusing, transforming through the power of the life endowed Spirit.