Treat everyone equally. However, it is also true that his project is critical in the peculiar sense of the unmasking of some previously concealed practice or aspect of some practice as an activity of frank-speech.
When Kant engages in parrhesia by exhorting his peers to use their own reason he is not issuing merely an exhortation, but, per his moral philosophy, he is telling them that their own practical reason obligates the use of reason consistent with universal law.
The prescription to know oneself was the means through which one cared for oneself, and Socrates cared for his own soul and the souls of others by using the practice of dialectic to force the examination of the truth of his own thought and conduct and that of his interlocutors.
Its roots go back a very long way. Ethical conduct, then, consists of the actions performed and capacities exercised intentionally by a subject for the purpose of engaging in morally approved conduct. The moral end of such practices was not to cultivate the attitude that abstention is a moral ideal, but rather to train him to become temperate and self-controlled.
Ethics is also important for those citizens who do not aspire to work in law enforcement. Their joint spiritual well-being was considered integral to the harmony of the human community.
Parrhesia and Self-Legislation Ethics, Foucault says, is the form that freedom takes when it is informed by reflection, and by this he means that freedom consists in reflectively informed ascetic practices or practices of self.