On the way...
On the way, they had killed a Muslim trader because of his expressing his allegiance and dedication for you. They also left a Dhimmi alone saying that there was no justification for killing him. When the Imam (a.s) received this intelligence, he sent a letter with a youth, `Abdullah ibn Wa`il, to Ziyad ibn Khasfah informing him that Khirrit and his men were headed towards Nafar and that they had killed one Muslim on the way.
The Imam (a.s) asked him to chase, apprehend and bring them back to al-Kūfah. If they resisted, he ordered him to fight them. `Abdullah ibn Wa`l must have gone a few steps when he returned and asked, “O Amir al-Mu’minin (a.s)! Do you permit me to join the contingent of Ziyad to fight the Khawarij?” The Imam (a.s) looked at the youth and said, “Yes! You too can join his contingent!
I hope that you will remain my helper in upholding the Truth and fighting the cruel people.” `Abdullah ibn Wa`l says: “By Allah!
The words with which he addressed me; I would not exchange them even with the red haired camels!”[1] When `Abdullah reached Dayr Abi-Mūsa and gave the letter from the Imam (a.s) to Ziyad ibn Khasfah, Ziyad looking at the steed, the arms and the bold look of `Abdullah, said, “How nice it would be if you remain with me!” `Abdullah said, “So is my wish as well and I have taken permission from Amir al-Mu’minin (a.s) for going with your contingent!” Therefore he joined Ziyad and the contingent started forthwith in pursuit of Banū-Najiyah enroute to Nafar.
When the pursuers reached Nafar, they were told that Banū-Najiyah had left for al-Jarjariyyah. Ziyad continued the hot pursuit and caught up with them at Mudar, a place lying between al-Basrah and Wasit. He put his camp near where Khirrit had halted. Khirrit came to Ziyad’s camp and asked the reason for his coming there. Ziyad said, “We are tired of the journey!
After some rest we shall tell you of the reason for our journey!” Ziyad rested for sometime, gave water to the animals and then went to al-Khirrit and asked him, “Why have you left al-Kūfah?” He said, “I do not like the ways of `Ali (a.s)! I am not in favor of his emirate.
Now I shall support those who want the caliphate to change hands through Shūra.” Ziyad asked, “Can we get a person through selection who has precedence in Islam, is the best scholar of the Qur’an and the Sunnah and is nearest to the Prophet (a.s)?” Khirrit said, “This cannot be ensured!” Ziyad now said, “You have killed a Muslim on the way.