I performed the Farewell Pilgrimage with the Messenger of Allah ﷺ. The Messenger of Allah ﷺ spoke at length, and then I heard him say, "If a mutilated slave," (I think she said, "a black slave") "is placed in authority over you and leads you according to the Book of Allah, then listen to him and obey."
حججت مع رسول الله ﷺ حجة الوداع قالت: فقال رسول الله ﷺ قولا كثيرا، ثم سمعته يقول: إن أمر عليكم عبد مجدع- حسبتها قالت: أسود- يقودكم بكتاب الله فاسمعوا له وأطيعوا.
Muslim narrated it in the Book of Leadership (1838), from Salama bin Shabib, who said, "Hasan bin Ayan told us, Maqil told us, from Zayd bin Abu Unaysa, from Yahya bin Husayn, from his grandmother Umm Husayn," and he mentioned it.