MATTHIAS HAUDEL (*)
If the ecumenical movement is looking for a basis for a common understanding of church and of mission, an obvious choice is the trinitarian understanding of God. Both the new trinitarian-based koinonia concept (1) in World Council of Churches (WCC) Faith and Order's thinking on church unity, and the increasingly trinitarian understanding of missio Dei in recent church thinking on the theology of mission, (2) are based on a return to the common trinitarian understanding of God. This article will analyze the causes and ecumenical consequences of this development, as well as the danger of unconsidered references to the trinitarian doctrine of the nature of God.
1. The central ecumenical significance of the doctrine of the Trinity
The growing recognition of the doctrine of the Trinity as an ecumenical basis for the churches' search for unity can be explained in no small measure by some historical observations. At the beginnings of the ecumenical movement in the 19th and 20th centuries, individual theologians of all the great confessions reiterated the opinion that the cause of fundamental ecclesiological differences lay in their different doctrines of the nature of God, and more particularly in the differing priorities set by their trinitarian theologies in referring to the Father, Son and Holy Spirit. (3) This view gradually established itself within the confessional families as well as in ecumenical dialogue, since the churches increasingly defined themselves with reference to the New Testament understanding of "communion" (koinonia, communio), in which believers' communion with God and one another is anchored in the trinitarian communion of Father, Son and Holy Spirit. This was true for the Second Vatican Council as well as the Luth eran World Federation (Curitiba 1990), the Anglican Communion or the Orthodox churches. (4)
Many bilateral dialogues have therefore concentrated on this trinitarian-based concept of church and of unity, but so has the multilateral dialogue sponsored by the WCC Faith and Order Commission. At the Fifth World Conference on Faith and Order at Santiago de Compostela in 1993, the first WCC worldwide church conference with official Roman Catholic participation, first attempts were made to develop the koinonia concept as a future concept of unity:
If we are to seek unity on a stable and healthy basis, we need a sound doctrine of God as Trinity and of the divine economy in Christ in relation to the work of the Holy Spirit. These doctrines are...indispensable presuppositions for an ecclesiology of communion as well as for all efforts to overcome division with the help of such an ecclesiology. (5)
The central ecumenical importance of the doctrine of the Trinity has become increasingly recognized in recent years, (6) growing out of the awareness of one-sided developments in trinitarian theology and their consequences for ecclesiology. It is also becoming increasingly clear that, in the last analysis, ecumenical progress can only be achieved with the help of an agreement on the understanding of the church, since the topic of "church" is "a sort of concentration" (7) of the Christian life. Linked to this was the realization, regained by turning back to the New Testament and the early church, that the understandings of church and of church unity are based primarily on the concept of God, thus on the doctrine of the Trinity. On the other hand, in the course of church history, certain ecclesiological interests have influenced the way the premises of trinitarian theology were represented.
On closer consideration, the determining of the relation between Christology and pneumatology, with its implications for the understanding of church, emerges as a central ecumenical problem, because the constitution and shape of the church depend on the definition of this relationship. It influences the relation between the authority of the whole church as the body of Christ and the charismatic authority of individual believers, between Spirit and institution, between ordained ministry and priesthood of all believers, between local church and church universal. …