Part of the emergence of early Christianity is the development of a 'Christian' language that describes and signifies it. In this process, faith was the decisive criterion for belonging and demarcation for Paul. Remarkably, Paul speaks about the non-believers - that is, those who do not belong to it - completely without polemics and the name does not appear in any catalog of vices. Examination of the term the unbelievers has shown that Paul used it less to describe a particular group as unbelieving or unbelieving, or to discuss why the unbelievers do not believe. Rather, the designation has a certain parenetic and identity-forming function: it serves to demarcate the believers from the non-believing past, it serves to demarcate them from the pagan world and it serves to (eschatological) reassurance of believers.