Imam al-Kazim (as): O Hisham, He who wants freedom from need without the need for riches, and comfort of the heart free from jealousy, and security in his faith should implore Allah, Mighty and Exalted, in his plea for Him to perfect his intellect. He who uses his intellect is content with that which suffices him and once he is content with what suffices him, he becomes free from need. And the one who is not content with that which suffices him [and craves for more] will never experience contentment. al-Kāfī