The World Council of Churches and the Lutheran World Federation - Communion of Churches have been attempting to formulate the goal of the visible unity of the church of Christ that would help them to reflect theologically on this goal and take the necessary steps to reaching it. Proceeding historically and systematically, this article offers a parallel study of the concepts and models of church unity developed within both ecumenical bodies until the establishment of the concept of koinonia.
This analysis shows both continuity and evolution of the understanding and formulation of unity and points also to similarities and differences in the ecclesiological frameworks of both communities. A special emphasis is thereby put on the relation between unity and diversity.