When Kharijites persisted rejecting Arbitration, Imam went and addressed them thus:
Were all of you with us in Siffin? They replied that some of them were but some of them were not. Imam said: Then divide yourselves into two groups. One of those who were in Siffin and other of those who were not present there, so that I may address each as I see suitable. Then he shouted to the people: Stop talking and keep quiet to listen to what I say. Turn your hearts to me. Whomever we ask for evidence, he should give it according to his knowledge about it.
Then he had a long conversation with them during which he said: When they had raised the Quran by way of deceit, craft, artifice and cheat, did you not say "They are our brothers and our comrades in accepting Islam. They want us to cease fighting, and ask for protection through the Book of Allah, the Glorified. Our opinion is to agree with them and to end their troubles." Then I said to you, "In this affair the outer side is Faith but the inner side is enmity. Its beginning is pity and the end is repentance. Consequently you should stick to your position, and remain steadfast on your path. You should press your teeth (put all your might) in jihad and should not pay heed to the shouts of the shouter If he is answered he would mislead, but if he is left he would be disgraced."
But when this thing (Arbitration) was done I found that you agreed to it. By Allah, if I had refused it, it would not have been obligatory on me. Nor would Allah have laid its sin on me. And by Allah, not that I have accepted it, I alone am the rightful person who should be followed, for certainly the Qur'an is with me. I never forsake it since I adopted its company. We have been with the Prophet in battles wherein those killed were fathers, sons, brothers and relations of one another. Nevertheless, every trouble and hardship just increased us in our belief, in our treading on the right path, in submission to (divine) command and in endurance of the pain of wounds.
We now had to fight our brethren in Islam because of entry into Islam of misguidance, crookedness, doubts and (wrong) interpretation. However, if we find any way by which Allah may collect us together in our disorder and by which we may come near each other in whatever common remains between us we would accept it and would give up everything else.