A friend whom you have been gaining during your whole life, you ought not to be displeased with in a moment. A stone is many years becoming a ruby - take care that you do not destroy it in an instant against another stone.
SaadiWhen a mean wretch cannot vie with another in virtue, out of his wickedness he begins to slander. The abject envious wretch will slander the virtuous man when absent, but when brought face to face his loquacious tongue becomes dumb.
SaadiThe wise man tells not what he knows. It is not prudent to sport with one's head by revealing the king's secrets.
Saadi