یَابْنَ الْغَطارِفَةِ الْأَنْجَبِینَ أنتَ اَمانٌ لِأَهلِ اِلأرضِ....

About the Kharijites and their opinion on Arbitration

We did not name people the arbitrators but we named the Qur'an the arbitrator. The Qur'an is a book covered between two flaps and it does not speak. It should therefore necessarily have an interpreter. Men alone can be such interpreters. When these people invited us to name the Qur'an as the arbitrator between us we could not be the party turning away from the Book of Allah. since Allah has said:
(And then if ye quarrel about anything refer it to Allah and the Prophet . . (Qur'an 4:59 . . .