This letter is from the servant and creature of Allah, Ali (a), Amir al-Mu'minin, to Kufiyites who are the leaders of Ansar and respectable persons.
After praising Allah and invoking His Blessings on the Holy Prophet (s) I want to throw light on the event of the assassination of Uthman and to make the whole affair as clear as if you were present on the occasion and were witnessing the event yourself.
People were dissatisfied with him and were accusing and blaming him. Out of the Muhajirs I was the only man who wanted to appease and pacify the people and who did not want to indulge in the activities of those dissatisfied persons, while Talha and Zubayr were instigating the populace in such a way that the least they said was worse than the worst that could be asserted or alleged against Uthman. Their whispering campaign was deadlier than the loudest propaganda which could be carried on; Aisha also exhibited extreme annoyance and anger against him. Under such conditions some persons resolved to kill him and they murdered him. Then everybody (friends and foes alike) came to me and took the oath of allegiance to me.
This was done without any desire, instigation, inducement, persuasion or compulsion and force on my part. They came to me of their own free-will, without hesitation, and with pleasure, ecstasy and joy.
Let it be known to you that the people of the city towards which the Holy Prophet (s) had migrated (Madina), is being deserted by its inhabitants, they are leaving it, it is seething with discontentment and rebellion. A seditious campaign has started against the Amir. I want you to come to the help of your Amir to fight against his enemies.