Sahih al-Bukhari 2874

It is related that the father of Ibrahim at-Tamimi said, "'Ali addressed us, saying, 'We have no book that we read but the Book of Allah and this paper which contains [judgements about] wounds and the ages of camels: "Madina is a sanctuary between 'Ayr to such-and-such a place. Whoever commits an improper action in it or gives refuge to someone who commits improper actions, on him is the curse of Allah, the angels and all people. Neither repentance nor ransom will be accepted from him. Whoever accepts the protectorship of other than his masters will have the like of that curse. The dhimma [covenant] of the Muslims is the same. Whoever breaks a Muslim's covenant, on him is the like of that curse."'" XI: When they say, "Saba'na" and do not say "We have become Muslim" (aslamna) properly Ibn 'Umar said, "Khalid began killing (them) and the Prophet, may Allah bless him and grant him peace, said, 'O Allah, I declare myself innocent to You of what Khalid has done.'" 'Umar said, "If someone says, 'Matras' [Persian for 'Do not fear'], he is granting security. Allah knows all the tongues." 'Umar said, "Speak, there is no harm." [Said to al-Hurmurzan and is said that it means to grant security] XII: Making peace and truces with the idolaters for money and other things. The wrong action of someone who does not abide by a treaty. The words of Allah, "If they incline to peace, incline to it as well." (8:61)