"There are many recurring ahadeeth from the Messenger of Allaah -sallAllaahu alayhi wa sallam- warning against them [the Khawaarij] and clarifying their characteristics and Allaah's ruling regarding them. This is why the Companions of the Messenger of Allaah - sallAllaahu alayhi wa sallam - fought against them, as did the rulers who came after them, throughout all periods of Islamic history. Even Ameer ul-Mumineen 'Uthmaan bin Affan was not saved from their attacks and evil plots, neither was Ameer ul-Mumineen 'Alee bin Abee Taalib nor was Ameer ul-Mumineen Muawiyyah bin Abee Sufyaan - RadhiAllaahu anhum ajmaeen. The Khalifah Umar bin Abdul Azeez -Rahimullaah- was not saved from them, they rebelled against him... so in reality they are the enemies of the people of Islaam and they are not pleased with any one of the Muslims ruling, no matter how good he is."