One swallow does not make a summer, neither does one fine day; similarly one day or brief time of happiness does not make a person entirely happy.

To perceive is to suffer.

For the things we have to learn before we can do them, we learn by doing them.

Men acquire a particular quality by constantly acting a particular way... you become just by performing just actions, temperate by performing temperate actions, brave by performing brave actions.

…existence is to all men a thing to be chosen and loved, and that we exist by virtue of activity (i.e. by living and acting), and that the handiwork is in a sense, the producer in activity; he loves his handiwork, therefore, because he loves existence.

...happiness does not consist in amusement. In fact, it would be strange if our end were amusement, and if we were to labor and suffer hardships all our life long merely to amuse ourselves.... The happy life is regarded as a life in conformity with virtue. It is a life which involves effort and is not spent in amusement....

All human happiness or misery takes the form of action; the end for which we live is a certain kind of action.

A friend is a second self.

Love is composed of a single soul inhabiting two bodies.