“The danger inherent in all the (necessary) work of theological statement is that it may go beyond the task of protecting the gospel and become a series of additions to the gospel,” writes Lesslie Newbigin (The Reunion of the Church, 16).
Denominations add to this inherent danger because “each group tends to accentuate the matters on which it is divided from the others and which justify its continued existence as a separate group. The force of its group egotism is thrown behind the particular emphasis or doctrine or practice which has led to its separate existence.”
Even if everyone agrees that what the group holds in common with others is more fundamental than what separates them, “the fact remains that what constitutes each group as a separate group is not what it holds in common with the others, but what it holds alone” (16).
As a result, each group has “more and more the character of a particular association based on a particular type of belief and practice, and it is more and more difficult to see either in any one of the groups, or in all of them collectively, the lineaments of the Church in the New Testament sense, the reconstituted human race, the new man in Christ. The separate groups are marked off from one another and from the world outside not simply by the fact of redemption and reconciliation in Christ, but by a whole variety of different shades of belief and piety.” The church appears to be a “series of particular associations based on a series of beliefs and practices which largely contradict each other and, taken together, cancel each other out” (16-17).
In the end, “These two things go together and mutually reinforce one another – the development of separated groups, an the addition to the Gospel of other things which do not belong to its essence” (18). To the gospel that each group says it upholds, each group adds its secret handshake and its shibboleth by which it preserves its inner ring and keeps others out.