I found a document in the hilt of the Messenger of Allah's ﷺ sword which read,"Among the most insolent of people are a man who strikes someone other than the one who struck him, a man who kills someone other than his killer, and a man who gives his loyalty to people other than those who showed him kindness. Whoever does any of this has rejected Allah and His Messenger. Allah will accept from him neither obligatory nor voluntary acts of worship.In matters of compensation, the lives of believers are equal in value, and the lowest among them may grant protection on behalf of all. A Muslim is not to be killed in retaliation for a disbeliever, nor is one under a covenant to be killed during the term of his covenant. People of two different religions do not inherit from one another. A woman is not to be married at the same time as her paternal aunt, nor at the same time as her maternal aunt. There is no prayer after the Asr prayer until the sun has set. A woman is not to travel for three nights except in the company of a Muharram."
وجدت في قائم سيف رسول الله ﷺ كتابا: إن أشد الناس عتوا من ضرب غير ضاربه، ورجل قتل غير، قاتله، ورجل تولى غير أهل نعمته، فمن فعل ذلك فقد كفر بالله ورسوله، لا يقبل الله منه صرفا، ولا عدلا، وفي الأجر المؤمنون تكافا دماؤهم، ويسعى بذمتهم أدناهم، لا يقتل مسلم بكافر، ولا ذو عهد في عهده، ولا يتوارث أهل ملتين، ولا تنكح المرأة على عمتها، ولا على خالتها، ولا صلاة بعد العصر حتى تغرب الشمس، ولا تسافر امرأة ثلاث ليال مع غير ذي محرم.
Abu Yaala (4757) narrated it from Abu Khaythama, who said, Ubaydullah bin Abdul-Majid narrated to us, Ubaydullah bin Abdul-Rahman bin Mawhab narrated to us, saying, I heard Malik bin Muhammad bin Abdul-Rahman say, I heard Amra bint Abdul-Rahman relate it from Ayesha, and he mentioned it. Ibn Abu Asim also narrated it in al-Diyat (107), as did Daraqutni (3/131) and Bayhaqi (8/29–30), all of them through the hadith of Ubaydullah bin Abdul-Majid, and he mentioned it.Its isnad is hasan because of Malik bin Muhammad Abu Rijal. Daraqutni was asked about him and said, "Salih," in Suwalat Barqani (498). He was the brother of Haritha bin Abu Rijal and Abdul-Rahman bin Abu Rijal, and they were known by their father's kunya. Abu Hatim said, "Malik is in a better state than his brothers." Ibn Hibban mentioned him in al-Thiqat (9/164). He is among the men of al-Tajil.On this subject there is also what was narrated from Ibn Abbas, that the Prophet ﷺ said, "The Muslims are equal in their bloods, and they are a hand against whoever opposes them, the lowest of them may act on behalf of their protection, and this binds even the highest of them." Ibn Majah narrated it (2683), and its isnad is extremely daif, for it contains Hanash, who is Husayn bin Qays Rahbi, Abu Ali Wasiti, nicknamed Hanash, and he is daif by the unanimous agreement of the scholars. Indeed Bukhari said, "His hadiths are extremely objectionable." Nasai said, "His hadith is to be abandoned."Likewise, what was narrated from Maqil bin Yasar is not sound either, that he said, the Messenger of Allah ﷺ said, "The Muslims are a hand against whoever opposes them, and they are equal in their bloods." Ibn Majah narrated it (2684), and it contains Abdul-Salam bin Abu Junub Madani. Abu Hatim said, "A shaykh whose hadith is to be abandoned," and the majority of the scholars likewise judged him daif.As for his saying, "they are equal in their bloods," equality here means that the noble and the lowly are equal in retaliation. Its meaning is that the bloods of the Muslims are equal in retaliation, so the noble is subject to retaliation for the lowly, and the elder for the younger, and no one is killed except the actual killer, even if the one killed was noble or wealthy, unlike what the people of the pre-Islamic era used to do. They were not satisfied, in the case of the blood of a noble person, with just the killer, but would kill a number of people from the killer's tribe instead.As for his saying, "the lowest of them may act on behalf of their protection," the "protection" here means the guarantee of safety, meaning that if the lowest man among the Muslims grants someone safety, it is not permissible for the rest to violate it, and this includes even a slave or a woman and others like them. There are details on this matter that are discussed in their proper places.As for his saying, "the believers are a hand against whoever opposes them," it means that the Muslims are brothers who help one another against others, meaning the disbelievers and the polytheists.