قال الحافظ ابن كثير الدمشقي ـ رحمه الله ـ في كتابه “البداية والنهاية”(١٠/ ٥٨٤-٥٨٥) عن ما سيفعله الخوارج بالأمة إذا قووا
إذْ لو قَووا هؤلاء لأفسدوا الأرض كلها عراقاً وشاماً، ولم يتركوا طفلاً ولا طفلة، ولا رجلاً ولا امرأة، لأن الناس عندهم قد فسدوا فساداً لا يصلحهم إلاّ القتل جملة
The Imaam, al-Haafiz Ibn Katheer (died, 774AH, rahimahullaah) stated in “Al-Bidaayah wan-Nihaayah” (10/584-585) regarding what the Khawaarij would do to the Ummah if they ever attained strength:
“If they ever gained strength, they would surely corrupt the whole of the earth, Iraq and Syria (Shaam) – they would not leave a baby, male or female, neither a man or a woman, because as far as they are concerned the people have caused corruption, a corruption that cannot be rectified except by mass killing.”
Today we see the reality of this affair at the hands of ISIS and other Jihadist insurgencies in Iraq and Syria. These fighters who in the name of Islam have instituted the mass killing of Muslims on the basis that rectification cannot take place except by the death of the masses. The murder perpetrated by the Khawaarij is worse than the murder committed by the sinners, because the sinners do not claim that they have license to kill from the Lord of the Worlds whilst the Khawaarij claim that Allaah, the Mighty and Majestic, has commanded them with this slaughter.
:حَدَّثَنَا سَهْلُ بْنُ أَبِي سَهْلٍ، حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ أَبِي غَالِبٍ، عَنْ أَبِي أُمَامَةَ، يَقُولُ
شَرُّ قَتْلَى قُتِلُوا تَحْتَ أَدِيمِ السَّمَاءِ وَخَيْرُ قَتْلَى مَنْ قَتَلُوا كِلاَبُ أَهْلِ النَّارِ قَدْ كَانَ هَؤُلاَءِ مُسْلِمِينَ فَصَارُوا كُفَّارًا . قُلْتُ يَا أَبَا أُمَامَةَ هَذَا شَىْءٌ تَقُولُهُ قَالَ بَلْ سَمِعْتُهُ مِنْ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ .
Abu Ghālib narrated from the Companion of the Prophet, Abu Umāmah (may Allah be pleased with him) that he said:
“(The Khawarij) are the worst of killers who are slain under the sky, and the best of those killed are those who were killed by them. Those (Khawarij) are the dogs of Hell. They used to be Muslim people but they became disbelievers.”
Abu Ghālibasked: “O Abu Umamah, is that your opinion?” He said: “No! Rather I heard it from the Messenger of Allah.”
(Reported by Ibn Mājah, no. 181, Hasan)
حَدَّثَنَا أَبُو كُرَيْبٍ، حَدَّثَنَا وَكِيعٌ، عَنِ الرَّبِيعِ بْنِ صَبِيحٍ، وَحَمَّادِ بْنِ سَلَمَةَ، عَنْ أَبِي غَالِبٍ، قَالَ رَأَى أَبُو أُمَامَةَ رُءُوسًا مَنْصُوبَةً عَلَى دَرَجِ مَسْجِدِ دِمَشْقَ فَقَالَ أَبُو أُمَامَةَ ” كِلاَبُ النَّارِ شَرُّ قَتْلَى تَحْتَ أَدِيمِ السَّمَاءِ خَيْرُ قَتْلَى مَنْ قَتَلُوهُ ”
. ثُمَّ قَرَأَ : ( يَوْمَ تَبْيَضُّ وُجُوهٌ وَتَسْوَدُّ وُجُوهٌ ) إِلَى آخِرِ الآيَةِ قُلْتُ لأَبِي أُمَامَةَ أَنْتَ سَمِعْتَهُ مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ لَوْ لَمْ أَسْمَعْهُ إِلاَّ مَرَّةً أَوْ مَرَّتَيْنِ أَوْ ثَلاَثًا أَوْ أَرْبَعًا حَتَّى عَدَّ سَبْعًا مَا حَدَّثْتُكُمُوهُ
Abu Ghālib also stated:
“Abu Umamah saw heads (of the Khawarij) hanging on the streets of Damascus. He said: ‘They are the dogs of the Hellfire and the worst of those those killed under the sky. The best dead men are those whom these [Khawarij] have killed.’ He then recited: “On the Day when some faces will become white and some faces will become black…” (3:106) until the end of the Ayah. I said to Abu Umamah: ‘Did you hear this from the Messenger of Allah (ﷺ)?’ He said: ‘If I had not heard it but one time, or two times, or three times, or four times – until he counted seven occasions – I would not have narrated it to you.'”
(Reported by At-Tirmidhee, no. 3270, Hasan)
The Khawarij have invented a lie against Allaah and His Messenger. It is for this reason Abu Umaamah (radiyallaahu ‘anhu) said that Allaah’s Messenger (salallaahu ‘alaihi wassallam) said regarding them:
“Dogs of the Hellfire, dogs of the Hellfire! The most evil of killers that are killed under the sky.”   Narrated by Aḥmed in his ‘Musnad‘, ibn Abī Shaybah in his ‘Muṣannaf’, at-Tirmidhee in his ‘Sunaan’ he declared it to be ‘ḥasan’. Tabrāni and Ḥākim in his ‘ṣaḥīḥ’ on the conditions of Muslim, ath-Thahabi said it was ṣaḥīḥ.
Al-Ājurī (d. 360 A.H.) said:
 Kitābush-Sharīʿah by al-Ājurī; Chapter: “Rebuking the Khawārij, and their evil Madhhab, the permissibility of killing them, and the reward for killing them and the one killed by them.” vol.1/325.
“Neither the scholars of old nor of these times, ever differed about the Khawārij. They regarded them as an evil people who were disobedient to Allāh, the Mighty and Majestic, and His Messenger even though they prayed, fasted and exerted themselves in worship, and all of this was of no benefit to them, even though they were apparent in enjoining the good and forbidding the evil, and that did not benefit them because they were a people who interpret the Qur’ān upon their desires.” 
Ibn al-Jawzī (d. 597 AH ) said:
 Talbīs Iblīs by Ibn Jawzī; Chapter: The Devil’s deception of the Khawārij, p.91.
“There are many long stories about them and their strange methodologies. I will not elaborate by mentioning them. Rather, the intent here is to study the deception of Iblīs, and how he deceived these fools, who reacted hastily to all that they encountered. They believed that ʿAlī bin Abī Tālib was wrong, and those who were with him from the Muhajirīn and the Ansār were also wrong, and that they themselves were upon the truth.
They made ḥalāl the blood of children, yet they did not allow the eating of any fruits of trees without paying for it. They tired themselves out with worship, and would frequently stay awake; yet they raised their swords against the Muslims.
And even Iblīs could not have imagined the extent of this evil. We seek refuge in Allāh from being forsaken.” 
ʿAbdul Malik bin Abī Ḥurrah al-Ḥanafi who said:
 Narrated by at-Tabari in his book Tārīkh (vol. 3 page 1)
“ʿAlī came out one day to deliver the Khutbah, and while he was speaking, the Khawārij gathered together on one side of the Masjid, so ʿAlī said, “Allāhu Akbar! A statement of truth but they intend falsehood by it.”
Yazīd bin ʿĀsim al-Muḥārabī (who was from the Khawārij) eagerly said, ‘Praise be to Allāh, our Lord will not abandon us, and we are in need of Him. O ʿAlī, are you trying to frighten us with death?!
As for me, then I swear by Allāh, I hope to strike you with this sword, very shortly, with the sharp side of the blade, then you will definitely know which of us is foremost for the fire.’
Then he left with the other Khawārij, he and his three brothers and he was the fourth. They were killed along with the Khawārij in the battle of an-Nahr and one of them was killed after that in the battle of Nākhīla.” 
And may of the Scholars have declared the Khawaarij insurgents to be unbelievers due to the numerous stern narrations concerning them. Bukhaaree reports (no. 5057) from Alee Ibn Abee Taalib (radiyallaahu ‘anhu) that Allaah’s Messenger (ﷺ) said:
يَأْتِي فِي آخِرِ الزَّمَانِ قَوْمٌ حُدَثَاءُ الأَسْنَانِ، سُفَهَاءُ الأَحْلاَمِ، يَقُولُونَ مِنْ خَيْرِ قَوْلِ الْبَرِيَّةِ، يَمْرُقُونَ مِنَ الإِسْلاَمِ كَمَا يَمْرُقُ السَّهْمُ مِنَ الرَّمِيَّةِ، لاَ يُجَاوِزُ إِيمَانُهُمْ حَنَاجِرَهُمْ، فَأَيْنَمَا لَقِيتُمُوهُمْ فَاقْتُلُوهُمْ، فَإِنَّ قَتْلَهُمْ أَجْرٌ لِمَنْ قَتَلَهُمْ يَوْمَ الْقِيَامَةِ
“There will appear in the last days young people with foolish thoughts and ideas. They will give talk with the best of speech, but they will go out of Islam as an arrow goes through its prey, their faith will not pass their throats. So, wherever you find them, kill them, for there will be a reward for their killers on the Day of Resurrection.”
They will be driven almost to insanity like creatures afflicted by rabies: Mu’aawiyah Ibn Abee Sufyaan (radiyallaahu ‘anhumaa) said that Allaah’s Messenger (ﷺ) said:
وَإِنَّهُ سَيَخْرُجُ مِنْ أُمَّتِي أَقْوَامٌ تَجَارَى بِهِمْ تِلْكَ الأَهْوَاءُ كَمَا يَتَجَارَى الْكَلْبُ لِصَاحِبِهِ ” . وَقَالَ عَمْرٌو ” الْكَلْبُ بِصَاحِبِهِ لاَ يَبْقَى مِنْهُ عِرْقٌ وَلاَ مَفْصِلٌ إِلاَّ دَخَلَهُ
“There will appear among my ummah people who will be dominated by desires like rabies which penetrates its victims. There remains not a vein and nor a joint but it penetrates it.” (Hasan: Abu Dawood 4597)
They will recite the Qur’an thinking it is in support of their ideas, yet it against them. They will fill their sermons with recitation of the Allaah’s Book, but they will not understand it as it was intended by Allaah.
يَخْرُجُ قَوْمٌ مِنْ أُمَّتِي يَقْرَءُونَ الْقُرْآنَ لَيْسَ قِرَاءَتُكُمْ إِلَى قِرَاءَتِهِمْ بِشَىْءٍ وَلاَ صَلاَتُكُمْ إِلَى صَلاَتِهِمْ بِشَىْءٍ وَلاَ صِيَامُكُمْ إِلَى صِيَامِهِمْ بِشَىْءٍ يَقْرَءُونَ الْقُرْآنَ يَحْسِبُونَ أَنَّهُ لَهُمْ وَهُوَ عَلَيْهِمْ لاَ تُجَاوِزُ صَلاَتُهُمْ تَرَاقِيَهُمْ يَمْرُقُونَ مِنَ الإِسْلاَمِ كَمَا يَمْرُقُ السَّهْمُ مِنَ الرَّمِيَّةِ
Zaid b. Wahb Juhani reported and he was among the force which was under the command of Ali and which set out to fight the Khawarij. ‘Ali (radiyallaahu ‘anhu) said:
O people, I heard the Messenger of Allah (ﷺ) say:
“There would arise from my Ummah a people who would recite the Qur’an, and your recital would seem insignificant as compared with their recital, your prayer nothing as compared with their prayer, and your fast nothing as compared with their fast. They will recite the Qur’an thinking that it supports them, whereas it is an evidence against them. Their prayer (salaah) does not get beyond their collar bone; they will shoot through Islam just as the arrow passes through the prey.”
Alee (radiyallaahu ‘anhu) said:
“If the army which is to encounter them were to know what goodness has been assured for them by their Messenger (ﷺ) they would completely rely upon this one deed alone. By Allah, I believe that these are the people (i.e. the Khawaarij) for they have shed forbidden blood, and raided the animals of the people. So go forth in the name of Allah to fight against them.”
Salama b. Kuhail mentioned that Zaid b. Wahb made me alight at every stage, till we crossed a bridge. ‘Abdullah b. Wahb ar-Raasibee was at the head of the Khawarij when we encountered them. Ar-Raasibee said to his army: “Throw the spears and draw out your swords from their sheaths, for I fear that they would attack you as they attacked you on the day of Haruraa.” So they went back and threw their spears and drew out their swords, and people fought against them with spears and the khawaarij were killed one after another and only two men were killed from the army of ‘Alee on that day. ‘Alee (radiyallaahu ‘anhu) said:
“Find out from among the dead bodies [of the Khawarij] the one who whose wrist would be without the arm, and the end of his wrist would be fleshy like the nipple of the breast.” This was because the Prophet informed them that such a man would be with the Khawarij. They searched but did not find him. ‘Alee then himself stood up and (walked) till he came to the people who had been killed one after another. Ali said: “Search them to the last,” and then they found him on the ground. ‘Ali then called out “Allahu Akbar (Allah is the Greatest).” Then he said, “Allah spoke the Truth and His Messenger (ﷺ) conveyed it.” Then `Abeedah Salmānee stood before him and said: “Commander of the Believers, by Allah, besides whom there is no god but He, tell me whether you heard this hadith from the Messenger of Allah (ﷺ).” He said: “Yes, by Allah, besides Whom there is no god but He.” He asked him to take an oath thrice and he took the oath. (Sahih Muslim 1066)
Ibn Bāz and the Khawarij: Possibly the greatest Salafi scholar of this era, Shaikh Ibn Bāz (Allah’s mercy be upon him) was asked concerning the terrorist Jamā’at ul-Jihaad and whether Muslims should co-operate with them?
They are not to be co-operated with, nor are they to be given salaams (salutations). Rather, they are to be cut off from, and the people are to be warned against their evil for they are a fitnah (tribulation) and are harmful to the Muslims – and they are the brothers of the Devil!
Source: From the taped cassette (no.11), recorded in the month of Dhul-Hijjah 1408H (1987CE) at ‘at-Tawiyyatul-Islaamiyyah’. This is the Salafi position towards these rebellious evil-doers. Ibn Baaz (rahimahullaah) also said:
“That which is apparent from the Prophetic narrations is that they are unbelievers. The correct and apparent view from the textual evidences is that on account of their extremism and their expulsion of Muslims from the fold of Islaam and declaring Muslims to be from the eternal inhabitants of the Hellfire, that they (themselves are in reality) unbelievers.”
The Prophet (ﷺ) said about them:
الْخَوَارِجُ كِلاَبُ النَّارِ
“The Khawaarij are the dogs of the Hellfire.” (Ibn Maajah, 173 from Ibn Abee Awfaa)
يَخْرُجُونَ مِنَ الدِّينِ كَمَا يَخْرُجُ السَّهْمُ مِنَ الرَّمِيَّةِ ثُمَّ لاَ يَعُودُونَ فِيهِ هُمْ شَرُّ الْخَلْقِ وَالْخَلِيقَةِ
“They will pass clean through the religion just as the arrow passes through the prey, and they will never come back to it. They would be the worst among the creation and the creatures.” (Saheeh Muslim 1067 from Abu Dharr)
يَقْتُلُونَ أَهْلَ الإِسْلاَمِ، وَيَدَعُونَ أَهْلَ الأَوْثَانِ، لَئِنْ أَنَا أَدْرَكْتُهُمْ لأَقْتُلَنَّهُمْ قَتْلَ عَادٍ
“They will kill the Muslims but will not disturb the idolaters. If I should live up to their time, I will kill them as the people of ‘Aad were annihilated (by Allaah).”
They began by the rebelling against the Prophet, then against Uthmaan (resulting in his assassination), then against Alee, when they became a fighting force, and one of them eventually killed Alee, and since they have appeared in each and every era rebelling against the Muslims and their rulers. And there will come a day when the Anti-Christ will appear in their ranks: Abdullaah bin ‘Umar (radiyallaahu anhumaa) said that the Messenger (sallallaahu alayhi wasallam) said:
A group will emerge who will recite the Qur’aan but it will not go beyond their throats. Every time a faction amongst them emerges it will be cut off. Every time a faction amongst them emerges it will be cut off, until the Dajjaal appears amongst them.”
This hadeeth is graded Hasan by Shaikh al-Albaanee in Saheeh al-Jaami’ (no. 8171), and it is narrated by Ibn Majah from Ibn Umar.
حَدَّثَنَا هِشَامُ بْنُ عَمَّارٍ، حَدَّثَنَا يَحْيَى بْنُ حَمْزَةَ، حَدَّثَنَا الأَوْزَاعِيُّ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ ” يَنْشَأُ نَشْءٌ يَقْرَءُونَ الْقُرْآنَ لاَ يُجَاوِزُ تَرَاقِيَهُمْ كُلَّمَا خَرَجَ قَرْنٌ قُطِعَ ” . قَالَ ابْنُ عُمَرَ سَمِعْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ يَقُولُ ” كُلَّمَا خَرَجَ قَرْنٌ قُطِعَ ” . أَكْثَرَ مِنْ عِشْرِينَ مَرَّةً ” حَتَّى يَخْرُجَ فِي عِرَاضِهِمُ الدَّجَّالُ ”
It was narrated from Ibn ‘Umar (may Allah be pleased with him) that he said: The Messenger of Allah said:
“There will emerge a people who will recite the Qur’an but it will not go any furthet than their collarbones. Whenever a group of them appears, they should be cut down.”
Ibn ‘Umar said: I heard the Messenger of Allah say: “Whenever a group of them appears, they should be cut down.” He said it more than twenty times, and then he said: “…until Dajjal, the false messiah, emerges among them.”
(Ibn Mājah, no. 179)
For a more detailed study of the Khawaarij, please refer to:
The Rise of Jihaadist Extremism in the West, published by Salafi Publications, Birmingham, UK.
The Religious Insurgency of the Khawarij translated and compiled by Abbas Abu Yahya, published by Salafi Publications, Birmingham, UK.