This thesis explores and examines the concept of the threefold Word of God in the theology of Karl Barth, particularly the third form of the Word of God, the gospel proclamation, and argues that this tertiary form of the Word of God is central to Barth’s own theology of the church. This thesis argues that Karl Barth revised the concept of the threefold Word of God in the later volumes of the Church Dogmatics, but did not seek to reject the concept nor reject Christ’s presence and God’s speech in the gospel declaration and in the life of the Christian community. This thesis argues that the threefold Word of God is a crucial element in Karl Barth’s vision of the church and an important theme for the whole of his theological project. Disregarded by the field of Barth studies and rejected by modern ecclesiologists, Barth’s description of the gospel declaration and its central role in the life together of the Christian community offers an important ecclesiological alternative to carry forward for both Reformed theology and modern ecclesiology. This dissertation makes three significant contributions. First, this thesis is the first of its kind to engage comprehensively with Karl Barth’s concept of the threefold Word of God and to make clear its later revision. Second, this dissertation offers a review of the contemporary scholarly literature related to Barth’s revision of the threefold Word of God, and addresses the theological and ecclesiological implications of this revision. Third, this dissertation makes a contribution to the fields of Barth studies and contemporary ecclesiology by arguing for the central place of the third form of the Word of God in Karl Barth’s conception of the Christian community.