Amir bin Wathila reported,
Nafi bin Abdul-Harith met Umar at Usfan. Umar had appointed him as governor over Mecca.Umar asked, "Whom have you appointed over the people of the valley?"He replied, "Ibn Abza."Umar asked, "Who is Ibn Abza?"He said, "One of our freedmen."Umar said, "You have appointed a freedman over them?"He replied, "He is a reciter of the Book of Allah 
, and he is knowledgeable in the laws of inheritance."Umar said, "Indeed, your Prophet has said, 'Allah raises some peoples by this Book and lowers others by it.'"
Azami 2249
Sahihعن عامر بن واثلة
أن نافع بن عبد الحارث لقي عمر بعسفان. وكان عمر يستعمله على مكة. فقال: من استعملت على أهل الوادي؟ فقال: ابن أبزى؟ قال: من ابن أبزى؟ قال: مولى من موالينا. قال: فاستخلفت عليهم مولى؟ قال: إنه قارئ لكتاب الله عز وجل. وإنه عالم بالفرائض. قال عمر: أما إن نبيكم قد قال: إن الله يرفع بهذا الكتاب أقواما، ويضع به آخرين.
Muslim narrated it in the chapter on the prayer of travelers (817), from Zuhayr bin Harb, who said, Yaqub bin Ibrahim narrated to us, who said, my father narrated to me, from Ibn Shihab, from Amir bin Wathila, and he related it.It is also reported from Ayesha that her slave boy, named Zakwan, used to lead her in prayer, reciting from the Quran. Bukhari mentioned it with a suspended chain, and Ibn Abu Dawud connected it fully in his book Kitab Masahif (797), saying, Ahmad bin Saeed bin Bishr informed us, Abdullah bin Wahb narrated to us, who said, Jareer bin Hazim informed me, from Ayub Sakhtiyani, from Ibn Abu Mulayka, from Ayesha, with the same content.He also narrated it through the route of Waki, and from him Ibn Abu Shayba (2/121, edited by Lahham), from Hisham bin Urwa, from Abu Bakr bin Abu Mulayka, from Ayesha, that she was led in prayer by a slave of hers whom she had promised to free after her death.Shafii narrated it in Umm (1/165) through the route of Ibn Jurayj, who said, Abdullah bin Ubaydullah bin Abu Mulayka informed me that they used to come to Ayesha at the upper part of the valley, he along with Ubayd bin Umayr, Miswar bin Makhrama, and many other people, and Abu Amr, the freedman of Ayesha, would lead them in prayer, though at that time he was still a slave boy who had not been freed.This Abu Amr mentioned is Zakwan. Ayesha had stipulated that he would be freed after her death, saying to him, "When you have buried me, you are free."It is established in the sahih hadith, from Abu Dharr, that he arrived at Rabaza while the call to prayer had already been given, and found a slave leading them in prayer. Abu Dharr said, "My beloved ﷺ instructed me to listen and obey, even if he were an Abyssinian slave with amputated limbs."Its origin is found in Sahih Muslim (1837), except that the story of the slave leading the prayer is not mentioned there. So Bayhaqi's attribution in Sunan al-Kubra (3/88) to Muslim is meant only to clarify the origin of the hadith, namely his saying, "My beloved ﷺ instructed me..."