Introduction

The most common word used as a term of address or as a self-designation in the New Testament is ἀδελφοί – ‘brothers and sisters’. While it is used in the New Testament of physical brothers, the predominant sense is as a term for ‘Christians’ or ‘fellow believers’, although it is also used by Jewish Christians to speak of non-Christian Jews. This metaphorical usage is found 271 times and occurs in all NT books with the exception of Titus and Jude. I will first discuss the usage of ἀδελφοί in the OT and other Jewish literature, and in the Greco-Roman world.

Background for the Metaphorical use of ἀδελφοί

Clearly, ἀδελφοί language comes from the sphere of the family. Much recent work has highlighted how important the family was in antiquity in both a Jewish and a Greco-Roman context. The family was the fundamental unit of ancient society, and was the primary group to which people belonged. It was from the family that people gained their sense of identity. It will become clear that when Christians called each other brother or sister they were drawing on the general understanding in their wider context of what this relationship entailed, even if they also developed it in particular ways. Hence we need to investigate this socio-historical context.