Starting from penance, this paper briefly analyses how the complete penal canon law based on the concept of crime and punishment was developed. However, this sanction system, while using the typical forms and institutions of secular criminal law, remains consistent with the ecclesial purpose of soul salvation. This purpose is found, for example, in the type of sanction, in the way it is imposed and in the personalization of the punishment. The contribution concludes with an explanation of single crimes in the Church law, with particular attention to the sexual abuses by clergy.