Two writings were found in the hilt of the Messenger of Allah's ﷺ sword. Among the most insolent of people are a man who strikes one who did not strike him, a man who kills one who did not kill him, and a man who gives his loyalty to other than the people who showed him favor. Whoever does any of this has disbelieved in Allah and His Messenger, and neither obligatory worship nor voluntary worship will be accepted from him.
وجد في قائم سيف رسول الله ﷺ كتابان: إن من أشد الناس عتوا رجل ضرب غير ضاربه، ورجل قتل غير قاتله، ورجل تولى غير أهل نعمته فمن فعل ذلك فقد كفر بالله ورسوله، لا يقبل منه صرف ولا عدل.
Ibn Abu Asim narrated it in al-Diyat (228), and this is his wording, and Abu Yaala (4757), Daraqutni (3/131), Hakim (4/349), and Bayhaqi (8/29–31) all narrated it, all of them from the hadith of Ubaydullah bin Abdul-Majid, who said, Ubaydullah bin Abdul-Rahman bin Mawhab narrated to us, he said, I heard Malik bin Muhammad bin Abdul-Rahman narrating from Amrah, from Ayesha, and he mentioned it in a longer hadith than this.Its chain is hasan because of Malik bin Muhammad bin Abdul-Rahman, for his hadith is hasan. See the book of inheritance, the chapter on "The people of the two religious communities do not inherit from one another."