We learn as much by others' failings as by their teachings. Examples of imperfection is just as useful for achieving perfection as are models of competence and perfection.

There is no one who cannot derive great help and great benefit from learning; but there are also only a few people who do not receive a great harm from the light and knowledge they have received by learning, unless they use their knowledge in a manner both fit and natural for them.

The ties of virtue ought to be closer than the ties of blood, since the good man is closer to another good man by their similarity of morals than the son is to his father by their similarity of face.

Self-love is almost always the ruling principle of our friendships. It makes us avoid all our obligations in unprofitable situations, and even causes us to forget our hostility towards our enemies when they become powerful enough to help us achieve fame or fortune.

Nothing can tell us so much about the general lawlessness of humanity as a perfect acquaintance with our own immoderate behavior. If we would think over our own impulses, we would recognize in our own souls the guiding principle of all vices which we reproach in other people; and if it is not in our very actions, it will be present at least in our impulses. There is no malice that self-love will not offer to our spirits so that we may exploit any occasion, and there are few people virtuous enough not to be tempted.

Criticism should awaken our attention, not inflame our anger. We should listen to, and not flee from, those who contradict us. Truth should be our cause, no matter in what manner it comes to us.

Pettiness of mind, ignorance and presumption are the cause of stubbornness, because stubborn people only want to believe what they themselves can imagine, and they can imagine very few things.