Musannaf Ibn Abi Shayba 26:588

Abu Khalid al-Ahmar narrated to us, from Yahya ibn Sa'id, from Abu Bakr ibn 'Amr ibn Hazm: That a woman from [the tribe of] Muharib gifted the *wala'* (patronage rights) of her slave to himself, and she emancipated him, and he emancipated himself. He said: So he gifted himself to 'Abd al-Rahman ibn 'Amr ibn Hazm. He said: Then she died, and the *mawali* (patrons) disputed before 'Uthman. He said: So 'Uthman called for evidence regarding what he said. He said: So he brought him the evidence. 'Uthman said: "Go, and form a *wala'* alliance with whomever you wish." Abu Bakr said: So he formed a *wala'* alliance with 'Abd al-Rahman ibn 'Amr ibn Hazm.