“There has been almost universal agreement that unity exists in a spiritual sense in the invisible church. Augustine, Luther, Calvin, and others ascribed to the invisible church a unity that is indivisible because of its center in the living Christ. The fundamentalists and evangelicals in the [Twentieth Century] came from similar backgrounds and, for the most part, agreed that there was (or at least would be in the eschaton) unity in the universal church. Therefore, the discussions of fellowship and separation had to center around the visible ‘church,’ whether that view of the church was seen to be local churches, denominations, associations or Christendom as a whole. The National Council of Churches, the National Association of Evangelicals, the American Council of Christian Churches and the various denominational groups connected to these broader organizations were all expressions of unity in one form or another as those within these organizations saw it.”

–Larry Oats, The Church of the Fundamentalists, 167