Bukhari

➊ Explanation:
The purpose here is to refute the Khawarij and the Mu'tazilah, who declare a person who commits a major sin (kabirah) to be a disbeliever (kafir). Ahnaf ibn Qays was among the supporters of Ali radi Allahu anhu in the Battle of Jamal. When Abu Bakrah narrated this hadith to him, he turned back.

Hafiz Ibn Hajar rahimahullah states that Abu Bakrah mentioned this hadith in an absolute sense, whereas the meaning of the hadith is that when two Muslims fight each other without a valid Shari'ah reason, it is prohibited. Fighting for the truth is itself permitted in the Qur'an, as is evident from the verse «فَإِنْ بَغَتْ إِحْدَاهُمَا عَلَى الْأُخْرَى» [الحجرات : 9]. Therefore, after this, Ahnaf remained with Ali radi Allahu anhu and did not act upon Abu Bakrah's opinion. From this, it is also understood that when presenting a hadith of the Prophet sallallahu alayhi wa sallam, it is necessary to consider its context and circumstances.

Hadith Commentary:
➊
This hadith also refutes the Khawarij, as despite the act of fighting, the Messenger of Allah (sallallahu alayhi wa sallam) called them "Muslims," which means that both parties, even in this state, did not leave the fold of Islam.
From the last part of the hadith, it is also understood that when an inner intention becomes firm and resolute, one will be held accountable for it, whereas in other narrations it is stated that Allah, the Exalted, has forgiven the inner thoughts of my ummah as long as they do not act upon them.
There is no contradiction between these two statements, because there will be no accountability for such thoughts that are not firm, i.e., those that come and go. However, for a firm intention and resolute determination, there will certainly be accountability, even if one is unable to act upon it.
(Sharh al-Kirmani: 1/444)

➋
Abu Bakrah (radi Allahu anhu) left this hadith in its absolute sense; on this basis, he himself did not participate in the Battle of Jamal and also prevented Ahnaf ibn Qays (radi Allahu anhu) from participating, even though the meaning of the hadith is that when Muslims come out to fight and the war is not based on truth, but rather motivated by the desire for dominion, tribalism, or similar motives, then both the killer and the killed are in Hellfire. However, if the intention is correct and the fighters are going forth in support of the truth, and every Muslim, with full caution and investigation, participates believing himself to be upon the truth, then both are destined for Paradise, because the Qur'an itself has permitted fighting for the truth.
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This is why Ahnaf ibn Qays (radi Allahu anhu) at that time turned back at the advice of Abu Bakrah (radi Allahu anhu), but when he reflected, he retracted his opinion and supported Ali (radi Allahu anhu). However, Abu Bakrah's (radi Allahu anhu) advice was based on sincerity and caution, aiming to reduce the intensity of the fighting.
(Fath al-Bari: 1/117)
From this, it is also understood that when presenting a Prophetic hadith, its context and circumstance must also be taken into consideration.

➌
The details of the Battle of Jamal will be mentioned later; however, in accordance with the topic, it is necessary to state here that those who participated in this battle believing Ali (radi Allahu anhu) to be upon the truth—whether they were killers or killed—are excluded from the warning mentioned in the hadith. And those whose purpose was merely to cause corruption—whether killers or killed—are, according to the hadith, in Hellfire.
Similarly, those who stood in support of the truth on the side of Sayyidah Aishah (radi Allahu anha), by Allah's permission, will enter Paradise. But those whose intention was to gain power, seek position, tribalism, or any other worldly motive, regarding them the Prophetic hadith is that both the killer and the killed are in Hellfire. The meaning of tribalism is to help someone merely because he is "one of our own," without investigating the circumstances.

Hadith Commentary:
➊
The period of turmoil refers to the time of the Battle of Jamal and the Battle of Siffin.
When Muslims come face to face with swords drawn against each other, then either both are mistaken in their interpretation and reasoning (ijtihad and ta’wil), or one is upon the truth and the other is mistaken.
There is no third possibility that both are upon the truth, because with Allah, the truth is one.

➋
In the first scenario, if there is hope for reconciliation between both parties, then it is necessary to strive for their reconciliation. If there is no hope for reconciliation, then one should separate from both.
One should break one’s swords and remain at home.
One should not take any part in the fighting whatsoever.

➌
In the second scenario, where one is wrong and the other is right, it is necessary to support the one who is upon the correct position.

➍
Here, another scenario is also possible: that neither party are mujtahids (qualified jurists), but both are oppressors fighting each other due to tribal partisanship or the desire for dominion. In this case as well, one should not support either party.
One should separate from both, but regarding the mutual disputes among the Companions (radi Allahu anhum ajma’in), it is safer to remain silent.
It is in no way appropriate to speak ill of them.

➎
In the hadith, those two Muslims are meant who, due to personal enmity, opposition, or hostility, are prepared to kill each other.
Even though only one is the killer, the slain was also eager to kill him; it just so happened that his attempt did not succeed, so he was killed. Therefore, both are deserving of punishment, and then their matter is referred to Allah: if He wills, He will punish them, and if He wills, He will forgive them.
But this ruling does not apply to the mujtahids, the details of which have already been explained.
Some scholars have interpreted the hadith to mean that both consider the killing of each other to be lawful.
(Fath al-Bari: 13/43)

➏
Another hadith further clarifies this.
Abu Hurairah (radi Allahu anhu) reports that the Messenger of Allah (sallallahu alayhi wa sallam) said:
“By the One in Whose hand is my soul! The world will not end until a time comes upon the people when the killer will not know why he killed, and the slain will not know why he was killed.”
It was asked: How will that be?
He (sallallahu alayhi wa sallam) replied:
“When killing and bloodshed become widespread.
In such circumstances, both the killer and the slain will be in Hellfire.
And Allah knows best.”
(Sahih Muslim, Al-Fitan, Hadith: 7304(2908))

Hadith Footnote:
However, by coincidence, he did not get this opportunity and was himself killed.
The meaning of the hadith is that when, without any legitimate (shar‘i) reason, a Muslim intends to kill another Muslim.

Hadith Commentary:
The meaning is that the one who was killed (the slain) was also intent on killing his opponent, but he did not get the opportunity, and thus he himself was killed.
Due to his malicious intent, he too will enter Hell.
This warning applies when he intends to kill another Muslim without any valid interpretation (ta’wil).
Its meaning is solely enmity and worldly desire, but whoever fought against rebels to end rebellion, or took up arms to repel an attacker and killed them, then he will not be included in this warning.
Apart from this, if a person is tasked with defending his wealth and honor, and in the process is killed, then he too will not be deserving of the aforementioned warning, because his objective is not to kill, but to defend himself.
(Fath al-Bari: 12/245)

Hadith Commentary:
Benefits and Issues:
This hadith establishes that if two people, without necessity, are intent on killing each other, then both—if Allah does not forgive them—will go to Hell to face punishment. However, if one of them raises the sword merely for self-defense and does not intend to kill the other, then he will be excused.

Since Abu Bakrah radi Allahu anhu considered the mutual conflict between Ali and Zubair radi Allahu anhu—the Battle of Jamal—as civil strife and a cause of harm, he forbade Ahnaf from supporting either side. However, since Ahnaf considered Ali radi Allahu anhu to be upon the truth, he later joined him.

Benefits and Issues:
➊ When a matter is not clear and explicit, and there is an aspect of truth on both sides, then in such a situation, remaining aloof and separate is more beneficial.

➋ The basis of actions is upon intentions.
When two people are engaged in conflict and there is no clear difference in their matters and intentions, then the slain is also considered like the killer; the only difference is that one succeeded in his attempt while the other was wounded.

(1) This hadith proves that killing a Muslim unjustly is a major sin and forbidden, and it also establishes that the one who commits this major sin becomes deserving of the fire of Hell.

(2) This noble hadith also establishes the ruling that when a person firmly intends to do any (good or bad) deed but, for some reason, is unable to act upon it, then according to his intention, that person becomes deserving of accountability or reward.

(3) The perpetrator of a major sin does not exit the fold of the Islamic community; rather, he remains a believer (mumin) and a Muslim, just as in the Noble Qur’an they are also called believers: {وَاِِنْ طَائِفَتَانِ مِنَ الْمُؤْمِنِیْنَ اقْتَتَلُوْا فَاَصْلِحُوْا بَیْنَہُمَا}, and in the aforementioned ahadith, the Messenger of Allah (sallallahu alayhi wa sallam) also called them Muslims.

(4) “They fall (into Hell)”—this is when both have the intention to fight, both are armed and naked (i.e., ready for battle), and both are intent on killing each other. However, if one gains the upper hand, then both the killer and the killed will equally be in Hell, because both had the intention to kill. This is also the meaning of this hadith: that both raise weapons against each other, as is explicitly mentioned in the subsequent ahadith. And Allah knows best.

Benefits and Issues:
(1)
Being on the edge of Hell means that, due to this mistake, there is a danger of both of them becoming inhabitants of Hell, but the opportunity to be saved from Hell still remains for them if they refrain from fighting.

(2)
The killing of a believer is an act that leads to Hell; however, this sin can be forgiven through repentance (tawbah) or retribution (qisas).