Fool, Miser, Sinful and Liar

The Imam Admonishing His Son:
Imam Ali ibn Abu Talib said the following to his son al- Hassan: O son! Learn four things and (a further) four things from me: Nothing will harm you if you practice them. The richest of all riches is intelligence; the biggest destitution is foolishness; the most wild of the wild is vanity, and the best achievement is goodness of the moral character.
O my son! You should avoid making friends with a fool because if he intends to benefit you, he will harm you. You should avoid making friends with a miser because he will run away from you when you need him the most. You should avoid making friends with a sinful person because he will sell you for nought. And you should avoid making friends with a liar because he is like a mirage, making you see far things as near and near things as far.