It is well known that monasticism was crucial to the development of repentance in early Christianity. With monasticism followed a renewal of the earlier practice with great importance for later Christian traditions. But were these changes just an internal development of earlier Christian teaching adjusted to new circumstances? Or were there also new impulses from external sources? In this paper, the teaching on repentance and confession in the Institutes and the Conferences by John Cassian (d. 435) and the Apophthegmata Patrum (from 5th/6th century), is compared with teachings related to the tendency towards the “care of the self” in late antique philosophy. In contrast to scholars who often have underscored the difference between the two traditions, this essay argues that the new monastic contribution to the earlier Christian practice of repentance can to a large extent be explained as adaptions of well-known practices or “technologies of the self” within late antique philosophy. Clement of Alexandria and Origen seems to have been crucial pioneers in this adaption, but traditions of philosophy were also filtered directly into the monastic tradition independently from these earlier Christian authors.