M.F. [...] A man possessed of a splendid ethos, who could be admired and put forward as an example, was someone who practiced freedom in a certain way. I don't think that a shift is needed for freedom to be conceived as ethos; it is immediately problematized as ethos. But extensive work by the self on the self is required for this practice of freedom to take shape in an ethos that is good, beautiful, honorable, estimable, memorable, and exemplary.
Q. Is this where you situate the analysis of power?
M.F. I think insofar as freedom for the Greeks signifies non-slavery—which is quite a different definition of freedom from our own—the problem is already entirely political. It is political in that non-slavery to others is a condition: a slave has no ethics. Freedom is thus inherently political. And it also has a political model insofar as being free means not being a slave to oneself and one's appetities, which means that with respect to oneself one establishes a certain relationship of domination, of mastery, which was called arkhé, or power, command.
Q. As you have stated, care of the self is in a certain sense care for others. In this sense, the care of the self is also always ethical, and ethical in itself.
M.F. What makes it ethical for the Greeks is not that it is care for others. The care of the self is ethical in itself; but it implies complex relationships with others insofar as this ethos of freedom is also a way of caring for others. This is why it is important for a free man who conducts himself as he should to be able to govern his wife, his children, his household; it is also the art of governing. Ethos also implies a relationship with others, insofar as the care of the self enables one to occupy his rightful position in the city, the community, of interpersonal relationships, whether as a magistrate or a friend. And the care of the self also implies a relationship with the other insofar as proper care of the self requires listening to the lessons of a master. One needs a guide, a counselor, a friend, someone who will be truthful with you. Thus the problem of relationships with others is present throughout the development of the care of the self.
(Taken from an interview given by Michel Foucault in January 1984, a few months before his death.)