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.

Imam Ali - Nahjul Belaga