Narrated `Ali:

We did not, write anything from the Prophet (ﷺ) except the Qur'an and what is written in this paper, (wherein) the Prophet (ﷺ) said, "Medina is a sanctuary from (the mountain of) Air to so and-so, therefore, whoever innovates (in it) an heresy or commits a sin, or gives shelter to such an innovator, will incur the Curse of Allah. the angels and all the people; and none of his compulsory or optional good deeds of worship will be accepted And the asylum granted by any Muslim Is to be secured by all the Muslims even if it is granted by one of the lowest social status among them. And whoever betrays a Muslim in this respect will incur the Curse of Allah, the angels and all the people, and his compulsory and optional good deeds of worship will not be accepted. And any freed slave will take as masters (befriends) people other than his own real masters who freed him without taking the permission of the latter, will incur the Curse of Allah, the angels and all the people, and his compulsory and optional good deeds of worship will not be accepted."