Alternative sources for this sermon
(see Bibliography for details of these texts)
Storm may overtake you while there may be none to prick you (for reforms). Shall I be witness to my becoming heretic after acceptance of Faith and fighting in the company of the Prophet?! "In that case I shall be misguided and I shall not be on the right path." (Qur'an, 6:56). So you should return to your evil places, and get back on the traces of your heels. Beware! Certainly you will meet, after me, overwhelming disgrace and sharp sword and tradition that will be adopted by the oppressors as a norm towards you. 
As-Sayyid ar-Radi says: In the words "wala baqiyah minkum abirun" used by Amir al-mu'minin the "abir" has been related with "ba'" and "ra'" and it has been taken from the Arab saying "rajulun abirun" which means the man who prunes the date-palm trees and improves them. In one version the word is "athir" and its meaning is "relator of good news." In my view this is more appropriate, as though Amir al-mu'minin intends to say that there should remain none to carry news. In one version the word appears as "abiz" with "za'" which means one who leaps. One who dies is also called "abiz".
Footnotes by translator:
.History corroborates that after Amir al-mu'minin, the Kharijites had to face all sorts of ignominy and disgrace and wherever they raised their heads for creating trouble, they were met with swords and spears. Thus Ziyad ibn Abih, `Ubaydullah ibn Ziyad, al-Hajjaj ibn Yusuf, Mus`ab ibn az-Zubayr and al-Muhallab ibn Abi Sufrah left no stone unturned in annihilating them from the surface of the globe, particularly al-Muhallab chased them for nineteen years, routed them thoroughly and rested only after completing their destruction.
At-Tabari writes that when ten thousand Kharijites collected in Silla wa sillibra (the name of a mountain in Ahwaz) then al-Muhallab faced them so steadfastly that he killed seven thousand Kharijites, while the remaining three thousand fled towards Kirman for life. But when the Governor of Persia noticed their rebellious activities he surrounded them in Sabur and killed a good number of them then and there. Those remained again fled to Isfahan and Kirman. From there they again formed a contingent and advanced towards Kufah via Basrah. Al-Harith ibn Abi Rabi`ah al-Makhzumi and `Abd ar-Rahman ibn Mikhnaf al-Azdi stood up with six thousand combatants to stop their advance, and turned them out of Iraq's boundaries. In this way successive encounters completely trampled their military power and turning them out of cities compelled them to roam about in the deserts. Afterwards also, when they rose in the form of groups they were crushed. (at-Ta'rikh, Vol. 2, pp. 580-591); Ibn al-Athir, Vol. 4, pp. 196-206).