Yasir Qadhi wrote on his Facebook page about Kharijites

lbn Kathir, the famous Muslim historian and student of lbn Taymiyya, writes in his aI-Bidaya wa-l-Nihaya (vol. 10, p. 584 paraphrased) :

And of the people whom the Kharijites killed was Abdullah b. Khabéb, the Companion of the Prophet (salla Allahu alayhi wa sallam). They captured him, along with his pregnant wife, and said, "Who are you?" "I am Abdullah b. Khabéb, the Companion of the Prophet (salla Allahu alayhi wa sallam), and you have brought harm and fear to me," he replied. 
"Don't worry about that," they said. "Narrate to us something that you hear from the Prophet (SAW)." He said, "I heard my father narrate that he heard the Prophet (SAW) say: 'There shall be trials and tribulations to come. The one who sits (and does not participate) is better than the one who stands, and the one who stands is better than the one who walks, and the one who walks is better than the one who runs.” [Point of the hadith: in times of chaos and bloodshed, don't be involved in killing and step aside]. When he narrated this hadith to them, they tightened his ropes and dragged him along. And as they were traveling, they came across a pig belonging to a Dhimmi. One of them killed the pig, but he was chastised by the others, "How dare you kill a pig belonging to a Dhimmi!" so he went to the owner and recompensed him. And another ate a date on the ground that had fallen from a garden, but he was chastised, "How could you eat from it without asking permission?" so he spit out the date and didn't swallow it.

Yet, despite this outward show of piety, it was these same people who slaughtered Abdullah b. Khabab, and when they came to kill his wife, she screamed out, "I am with child! Do you not fear Allah?!"

Not only did they kill her, they slit her stomach to kill her child as well.

- end quote from Ibn Kathir.

And all of this is but some of what our history books narrate regarding the fanaticism of the Kharaijites, whom our Prophet (salla Allahu alayhi wa sallam) predicted would irritate the Ummah until the end of times. From their characteristics:

- blanket takfir of all those who oppose them
- self-taught and trained in Islamic sciences
- outer shell of piety, whilst living an inner life of sin
- typically young in age, foolish in their goals
- unable to engage in dialogue, for all they know is the language of killing and violence
- their slogans sound good, but their actions belie their sweet talk
- they will leave the true enemies of Islam, and target the people of Islam

All of these, and more, have been predicted in the traditions, and we see these prophetic predictions verified and proven every single day.