Honest and sincere acts mislead the wicked and cause them to lose their path to their own goals, because mean-spirited people usually believe that people never act without deceit.

It is sometimes useful to pretend we are deceived, because when we show a deceiving man that we see through his artifices, we only encourage him to increase his deceptions.

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.

To be too dissatisfied with ourselves is a weakness. To be too satisfied with ourselves is a stupidity.

Although we should not love our friends for the good that they do us, it is a sign that they do not love us much if they do not do us good when they have the power to do so.

It is vain and useless to survey everything that goes on in the world if our study does not help us mend our ways.

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.