This article is an analysis of the historical roots and ethical semantics of the social work concept ‘a marginal person, a client’ (the Greek words ξένος, ksenos and αςτος, astos). The question is relevant in modern social work in relation to the concept of ‘strange’ or ‘marginal’. The article analyses how the concepts ‘strange’, ‘other’ and marginal’ have re-entered the modern world from the Ancient world, as they were used in Ancient Syria (in the fourth century), Greece, and Medieval Europe. However, nowadays in social work theory they should be described anew using the discourses of social work and anthropology. The article explores the question of how to communicate with the ‘other’ or marginal person, based on reciprocity and internal solidarity.