Musnad Ahmad Hadith 959

We did such and such. And he would say: Allah and his Messenger spoke the truth. Al-Ashtar said to him: What you say is becoming widespread among the people. Is it something that the Messenger of Allah (ﷺ) advised you to say? ‘Ali (رضي الله عنه) said: The Messenger of Allah (ﷺ) did not advise me to say anything to the exclusion of other people, except something I heard from him and it is written in a document in the sheath of my sword. They kept on at him until he took out a document, in which it said: `Whoever commits an offence or gives refuge to an offender, upon him be the curse of Allah and the angels and all the people; no nafl or obligatory act of worship will be accepted from him.” And in it was said. Ibraheem declared Makkah to be a sanctuary and I declare Madinah to be a sanctuary; the area between its two lava fields and all of its territory is sacred. It`s grasses are not to be cut, and its game is not to be disturbed, and its lost property is not to be picked up except by the one who announces it, and no tree is to be cut in it, except what a man needs to feed his camel. And no weapon is to be carried in it for fighting.` And in it was said: `All the believers are equal in respect of blood [i.e., their lives are of equal value] . The protection offered by the least among them is to be honoured. They should be united as one against their enemies. A believer is not to be killed (in retaliation) for a disbeliever, nor one who has a covenant during the covenant.