The debate on the relationship between the Rule of the Community (S) and the Damascus Document (D) can be distorted by concentrating on the differences between the documents, without a clear appreciation of the significance of their mutual correspondences. The concept of Idem identity is here adopted to demonstrate that what the movement was considered to be is at least as important to ask as who its members were considered (and considered themselves) to be (questions of their ipse identity). The movement could be perceived to be the same, persisting overtime, despite various kinds of differences. The article seeks to identify critical elements of diversity allowed within the same movement. An experiment on the Idem identity is provided by looking at the rule documents and the admission in particular. In its shared social identity, the movement seems to depict itself rather in terms of its activities such as counsel and qualifications than particular forms of communities and organizations.