The Ruling on Killing the Aggressor

This is a letter we received from Sulayman Mubarak 'Umar Mukhash from Riyadh. He says: What is the ruling of the Shari'ah in the case where a Muslim is subjected to violation of his honor while he is on a land, sea, or air journey, and he may call out to you for help? If you respond to that call out of religious, brotherly, and humanitarian motives, and during your defense of him you end up killing one of the aggressive, encroaching individuals, knowing that you did not spare any means to avoid killing him, but you were compelled to do so in order to repel the aggression against the honor of your brother who sought your help, who is with women, or who is being attacked in his honor, his wealth, or the like? Please inform us of the situation if there is killing involved, and does the saying of the Messenger of Allah (peace and blessings be upon him), "The killer and the killed are in the Fire," apply to this? Please inform us, may Allah reward you?
Answer: It is obligatory for Muslims to enjoin good and forbid evil wherever they are, whether on an airplane or elsewhere. A Muslim must help his brother in truth, and he has no right to help him in falsehood. He must defend his honor, so it is not befitting for him to sit with those who backbite; rather, he should rebuke them, admonish them, and remind them so that they do not backbite their brothers. This is because Allah (Glorified and Exalted is He) says: [Surah al-Hujurat: 12]. Backbiting is a wrong and one of the major sins.
So if you sit with a group of people who are backbiting others, you are a partner with them in the sin, unless you rebuke them or leave them. You must rebuke them; if they respond, praise be to Allah. If not, you must leave them and not sit with them in what Allah (Mighty and Majestic) has forbidden. And if Zayd transgresses against your brother, the Messenger of Allah (peace and blessings be upon him) said: .
In another wording: meaning you restrain him from injustice. This is helping the wrongdoer by preventing him from injustice. If someone transgresses against your brother, you intervene between them with kindness, by preventing the aggression. You and your brothers all intervene between them, resolving their problem, preventing this one from that one. If they have a claim or dispute afterwards, they should contact the court. But do not leave them on the airplane, in the car, on the ship, or in any place to fight and for one to wrong the other. No, rather intervene between them, resolve their problem, prevent this one from that one, and be companions of good and helpers in good. Help the oppressed and prevent the oppressor. This is what is obligatory upon you without killing. As for killing, no, this one is not killed nor that one. Rather, you must intervene between them to prevent transgression. As for killing, it is not permissible to proceed to killing. Rather, this is postponed until the court looks into their case. And whoever deserves killing because he did what necessitates killing, that is a different matter.
So the result is that you must help your brother in repelling his grievance and in preventing injustice from him without killing. As for killing, no; because killing requires care and requires looking into the causes of the killing. You only restrain between them, preventing this one from transgressing against that one. You and your brothers present cooperate to prevent this one from wronging his brother. If they have claims, they are postponed until they reach their destination or another country where there is a judiciary, so they litigate before the judges regarding what is disputed between them.
But the issue of killing is a big and great matter, so no one has the right to kill the other. Rather, they must stop, and their supporters must intervene between them and that so that no fighting occurs. Yes.
The presenter: May Allah reward you. If the person was with women and he was in the desert, and his honor was violated, and he called out to someone for help, and the owner of the women and his helper were compelled to defend their honor, and the matter reached... killing.
The Shaykh: He must defend himself. If he is killed, he is a martyr. And if the wrongdoer is killed, there is no blame on him.
The presenter: Perhaps this is what the questioner intended, O Shaykh.
The Shaykh: The point is that if his honor is violated or someone intends to kill him, he has the right to defend himself. It is established in the authentic hadith that This is a dispensation granted by the Prophet (peace and blessings be upon him) for defense. He defends his wealth, so honor is greater and religion is greater. If the wrongdoer intends to transgress against his wife, his daughter, or his mother, he has the right to prevent that by whatever means he can. If he can prevent it by speech or with a stick, he prevents it. If he cannot prevent it except by killing, such as with a sword or a knife or the like, then he has that right. If he is truthful regarding the authorities, there is no retaliation upon him if what indicates his truthfulness is established. If this is not established, it is referred to the court to investigate the facts and look into the incident. If what indicates his truthfulness is established, otherwise he is subject to retaliation. Yes.
The presenter: May Allah reward you.