It wasnarrated from Abu Dharr that he reached Rabadhah when theIqamah forthe prayer had already been given, and there was a slaveleading themin prayer. It was said:
"This is Abu Dharr," so he (theslave)started to move back. But Abu Dharr said: "My close friend(i.e.,the Prophet (ﷺ)) told me to listen and obey, even if (theleaderwas) an Ethiopian slave with amputated limbs."
English reference: Vol. 4, Book 24, Hadith 2862
Arabic reference: Book 24, Hadith 2972