Muslim

Hadith Commentary:
Imam Muslim narrated from Abu Dharr that the Khawarij are the worst among all creatures, and al-Bazzar narrated it marfu‘an (ascribed to the Prophet): the Messenger of Allah (sallallahu alayhi wa sallam) mentioned the Khawarij and said, "They will be the worst people in my Ummah, and the best people of my Ummah will kill them."

The Khawarij are a well-known sect whose beginnings trace back to the last period of the caliphate of Uthman (radi Allahu anhu). Outwardly, these people were very devout, ascetic, and reciters of the Qur’an, but there was not even a trace of the light of the Qur’an in their hearts. When Ali (radi Allahu anhu) became caliph, these people initially remained with him. After the Battle of Siffin had taken place and the decision for arbitration was agreed upon, at that time these people separated from Ali (radi Allahu anhu) as well. They began to criticize him, saying, "How could he accept arbitration, when Allah has said: ﴿إنِ الحکمُ إلَّا ِﷲِ﴾ (al-An‘am: 57) — 'The decision is only for Allah.'"

Their leader was Abdullah ibn Kawwa. Ali (radi Allahu anhu) sent Abdullah ibn Abbas (radi Allahu anhuma) to advise them, and he himself also tried to explain to them, but they did not accept. Eventually, Ali (radi Allahu anhu) killed them in the Battle of Nahrawan. A few people managed to escape. Among them was Abdur Rahman ibn Muljam, who martyred Ali (radi Allahu anhu).

These wretched Khawarij declare Ali, Uthman, Aisha, Talha, and Zubair (radi Allahu anhum) to be disbelievers, and they declare anyone who commits a major sin to be eternally in Hell. They consider it obligatory for a woman to make up prayers missed during menstruation (hayd). They interpret the Qur’an according to their own desires, and apply verses revealed about disbelievers to the believers.

The intended meaning of the word "Khariji" is "rebel," i.e., those who rebelled against Ali (radi Allahu anhu). In reality, they arose in opposition to the Rawafid (Rafidites), and became a cause for further division within the Ummah. May Allah disgrace them all.

The group that avoids all these disputes and walks upon the straight path is the group of Ahl al-Sunnah wa’l-Jama‘ah, who honor both Ali (radi Allahu anhu) and Mu‘awiyah (radi Allahu anhu), and pray for the forgiveness of all of them.

﴿تِلْكَ اُمَّةٌ قَدْ خَلَتْۚ-لَهَا مَا كَسَبَتْ وَ لَكُمْ مَّا كَسَبْتُمْ﴾ (al-Baqarah: 134)
("That was a nation which has passed on. It will have [the consequence of] what it earned, and you will have what you have earned.")

Hadith Commentary:
(1)
In the preceding ahadith, there was mention of the Haruriyyah; in this hadith, it is explicitly stated that what is meant by this is the group of the Khawarij.
(2)
It is also understood from this hadith that their emergence occurred at the time of disagreement among the noble Companions (radi Allahu anhum); thus, this group was eliminated by Ali (radi Allahu anhu) and his companions.
Among them, the individual appeared regarding whom the Messenger of Allah (sallallahu alayhi wa sallam) had indicated.
(3)
Regarding the Khawarij, ahadith are narrated from approximately twenty-five noble Companions (radi Allahu anhum), in which mention of this tribulation is found.
The noble Companions (radi Allahu anhum) suppressed this tribulation.
They had great enmity towards Ali (radi Allahu anhu).
Just as the Rawafid went astray in their excessive devotion to him, likewise the Khawarij deviated from the straight path due to their enmity and hostility towards him.
May Allah forsake them all in this world and the Hereafter. Ameen, O Lord of the worlds.