Day and night keep the fear of Allah in your mind. Be afraid of this alluring and vicious world, never trust it. If you do not check yourself from the desire of acquiring inordinate things then your mind will surely drive you towards losses. Therefore, have a complete watch and command over yourself and at the time of anger and annoyance see that you do not lose your temper.
Qur'an, 7:87
While leaving Madina for Basra, Imam Ali (a) wrote the following letter to the people of Kufa. It is a wonderful epistle. It invites people to judge his intentions and actions.