Trust not in present prosperity, for it is a departing guest.
Reserve the white coin for the black day.
If it be in your power to do harm to your enemy—do it not, but forgive him and win his thanks.
The eye cannot contend with pointed steel.
Be cautious even where you are most sure.
Poverty is a chain which restrains men from doing much evil.
If you would know what a man hath, look not to what he gains but to what he spends.
Nothing can be concealed except that which is not.
The best friend is he who changeth not with the changes of time.
Every rule has exceptions.