Sunan ad-Darimi

Sayyiduna Aws bin Abi Aws Thaqafi (may Allah be pleased with him) said: I came to the service of the Messenger of Allah (peace and blessings be upon him) with the delegation of Banu Thaqif, and I was in one corner of the tent in which there was no one except the Messenger of Allah (peace and blessings be upon him). The Prophet (peace and blessings be upon him) was sleeping, when suddenly a companion came to him and whispered. The Prophet (peace and blessings be upon him) said: "Go and kill him." He said: Then the Prophet (peace and blessings be upon him) said: "Does he not testify that there is no god but Allah?" Shu’bah said: I am unsure whether he mentioned the testimony of Muhammad (peace and blessings be upon him) or not. They said: Yes (he testifies to it). He said: "I have been commanded to fight the people until they say La ilaha illallah, and when they say it, then their blood and wealth are protected from me except by the right of Islam (i.e., legal punishment or retribution), and their reckoning is with Allah." The narrator said: This person had killed Abu Mas’ud, and he did not die until the best man of Ta’if had passed away.