It has been narrated on the authority of Abu Dharr who said:My friend (i. e. the Holy Prophet) advised me to listen (to the man in position of authority) and obey (him) even if he were a slave maimed (and disabled)

In another version of the tradition, we have the wording:" An Abyssinian slave maimed and disabled

Abu 'Imran narrated this hadith with a slight change of wording