Imam Ali once said to his son Imam Hasan, My son, learn four things from me and through them you will learn four more. If you keep them in mind your actions will not bring any harm to you: The greatest wealth is Wisdom; the greatest poverty is stupidity; the worst unsociableness is that of vanity and self-glorification; and the best nobility of descent exhibits itself in politeness and in refinement of manner. The next four things, my son, are: 'Do not make friendship with a fool because when he will try to do you good he will do you harm; do not make a miser your friend because he will run away from you at the time of your dire need; do not be friendly with a vicious and wicked person because he will sell you and your friendship at the cheapest price and do not make friend of a liar because like a mirage he will make you visualize very near the things which lie at a great distance and will make you see at the great distance the things which are near to you'.