Sayyiduna Ka'b bin Malik (may Allah be pleased with him) narrates: "Mula'ib al-Asinnah" came to the Prophet (peace and blessings be upon him) bringing a gift. The Prophet (peace and blessings be upon him) offered Islam to him, but he refused to accept Islam. The Prophet (peace and blessings be upon him) said: "I do not accept the gift of a polytheist." He said: "Then send whomever you wish to the people of Najd; I grant them protection." So the Prophet (peace and blessings be upon him) sent some people to them, one of whom was Sayyiduna al-Mundhir bin Amr (may Allah be pleased with him); he is the one who is called "al-Mu'taq li-Yamut" (the one set free to die) or "U'tiqa ind al-Mawt" (he was set free at death). Amir bin al-Tufayl tried to rally Banu Amir against them, but they refused to obey him, and they refused to violate the protection given by "Mula'ib al-Asinnah". Amir then called on Banu Sulaym to gather against them (i.e. the Companions), and they agreed to his call. About a hundred archers together came after them; they caught up with them at "Bi'r Ma'unah" and killed them; only Sayyiduna Amr bin Umayyah (may Allah be pleased with him) survived.
Al-Tabarani recorded it, and its narrators are the narrators of the Sahih.