From Annex 1, which Frédéric Gros in his Introductory Notice hypothesises could have been intended as either the sketch of an introduction to the book or a personal synthesis, we can draw several guiding principles that Foucault wishes to demonstrate:
1) Prescriptive Continuity: there is a relatively stable common « prescriptive core » localisable within Christianity but pre-dating it, and traceable to « pagan authors of the Hellenistic and Roman epochs ».
2) Multiple Embedding: the elements of this common prescriptive core can be found in the writings of early Christian apologists, going back to the Second Century, embedded in both theological doctrines and practical moral precepts.
3) Meaning Incommensurability: the elements of this prescriptive core are shared by writers of Late Antiquity and of early Christianity but their signification is quite different as the relations between subjectivity and truth are different in the two configurations.
4a) Epistemico-ethical Reconfiguration: there is not a linear passage from pagan permissiveness to Christian repressiveness nor a simple revision of the demarcation between permitted and forbidden, but rather a change in the analysis of the domain of pleasures (aphrodisia) and of the subject’s prescribed mode of relation to this domain.
4b) Mutability of Experience: « Thus it is not so much the law and its content that changed, but experience, as a condition of knowledge ».
I would like to add a few comments:
The continuity of the common prescriptive core cannot be explained by or founded in an underlying commonality of experience. The common prescriptive core does not imply a common experiential core.
The historical progression from Platonic and Stoic paganism to Christian Apologetics cannot be seen as a cumulative progress (adding God as Logos as legitimating instance to a pre-existing set of precepts grounded in Nature and in Reason) nor as a de-cumulative regress (subtracting pleasures from the list of permitted comportments).
There is no common core of signification nor even of experience, but a mutation in the relations between subjectivity and truth that underlie the relations between experience and knowledge.
The choice of the analysis of the domain of « pleasures » is part of Foucault’s more general problematisation of the psychoanalytic notion of « desire ».
We know from the lectures on THE HERMENEUTICS OF THE SUBJECT that concerning the question of the relation between subject and truth Foucault declares affinity with the primacy of a Heideggerian approach over a Lacanian one, conceived of as insufficiently conceptually transformative.