In early Christianity, conflict resolution that involved decision about exclusion and reintegration of community members was often ritualized as excommunication, penance, confession of sins and intercession. Mediation of divine forgiveness of sin was central to the rituals that reintegrated transgressing community members and reconciled them with the community. This paper discusses confession and penance as costly signalling of commitment. The concept of "cost" as used in costly signaling theory is evaluated in relation to these rituals.