Philosophy as a Way of Life by Pierre Hadot is subtitled "Spiritual Exercises from Socrates to Foucault" (translated by Michael Chase). It's heavy reading for a lightweight mind like mine, but in browsing it I've run across a number of memorable thoughts.
from Chapter 1, "Forms of Life and Forms of Discourse in Ancient Philosophy":
By the time of the Platonic dialogues Socrates was called atopos, that is, "unclassifiable." What makes him atopos is precisely the fact that he is a "philo-sopher" in the etymological sense of the word; that is, he is in love with wisdom. For wisdom, says Diotima in Plato's Symposium, is not a human state, it is a state of perfection of being and knowledge that can only be divine. It is the love of this wisdom, which is foreign to the world, that makes the philosopher a stranger in it.
from Chapter 3, "Spiritual Exercises", section 1, "Learning to Live":
Spiritual exercises can be best observed in the context of Hellenistic and Roman schools of philosophy. The Stoics, for instance, declared explicitly that philosophy, for them, was an "exercise." In their view, philosophy did not consist in teaching an abstract theory --- much less in the exegesis of texts --- but rather in the art of living. It is a concrete attitude and determinate lifestyle, which engages the whole of existence. The philosophical act is not situated merely on the cognitive level, but on that of the self and of being. It is a progress which causes us to be more fully, and makes us better. It is a conversion which turns our entire life upside down, changing the life of the person who goes through it. It raises the individual from an inauthentic condition of life, darkened by unconsciousness and harassed by worry, to an authentic state of life, in which he attains self-consciousness, an exact vision of the world, inner peace, and freedom.
from later in Chapter 3, section 4, "Learning How to Read:"
With the help of these exercises, we should be able to attain to wisdom; that is, to a state of complete liberation from the passions, utter lucidity, knowledge of ourselves and of the world. In fact, for Plato, Aristotle, the Epicureans, and the Stoics, such an ideal of human perfection serves to define divine perfection, a state by definition inaccessible to man. With the possible exception of the Epicurean school, wisdom was conceived as an ideal after which one strives without the hope of ever attaining it. Under normal circumstances, the only state accessible to man is philo-sophia: the love of, or progress toward, wisdom. For this reason, spiritual exercises must be taken up again and again, in an ever-renewed effort.
The philosopher lives in an intermediate state. He is not a sage, but his is not a non-sage, either. He is therefore constantly torn between the non-philosophical and the philosophical life, between the domain of the habitual and the everyday, on the one hand, and, on the other, the domain of consciousness and lucidity. To the same extent that the philosophical life is equivalent to the practice of spiritual exercises, it is also a tearing away from everyday life. It is a conversion, a total transformation of one's vision, life-style, and behavior.
from Chapter 10, "The Sage and the World":
In a sense, one might say that the world of science and the world of philosophy are both, in their own way, opposed to the world of habitual perception. In the case of science, this opposition takes the form of the elimination of perception. Science discloses to us a universe reduced, by both mathematical and technological means, to its quantitative aspects. Philosophy, for its part, deepens and transforms habitual perception, forcing us to become aware of the very fact that we are perceiving the world, and that the world is that which we perceive.
from Chapter 11, "Philosophy as a Way of Life":
Philosophy in antiquity was an exercise practiced at each instant. It invites us to concentrate on each instant of life, to become aware of the infinite value of each present moment, once we have replaced it within the perspective of the cosmos. The exercise of wisdom entails a cosmic dimension. Whereas the average person has lost touch with the world, and does not see the world qua world, but rather treats the world as a means of satisfying his desires, the sage never ceases to have the whole constantly present to mind. He thinks and acts within a cosmic perspective. He has the feeling of belonging to a whole which goes beyond the limits of his individuality. ...
from the "Postscript: An Interview with Pierre Hadot" (by Michael Chase):
Everything which is "technical" in the broad sense of the term, whether we are talking about the exact sciences or the humanistic sciences, is perfectly able to be communicated by teaching or conversation. But everything that touches the domain of the existential --- which is what is most important for human beings --- for instance, our feeling of existence, our impressions when faced by death, our perception of nature, our sensations, and a fortiori the mystical experience, is not directly communicable. The phrases we use to describe them are conventional and banal; we realize this when we try to console someone over the loss of a loved one. That's why it often happens that a poem or a biography are more philosophical than a philosophical treatise, simply because they allow us to glimpse this unsayable in an indirect way. Here again, we find the kind of mysticism evoked in Wittgenstein's Tractatus: "There is indeed the inexpressible. This shows itself; it is the mystical."