حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي عِمْرَانَ الْجَوْنِيِّ، عَنْ عَبْدِ اللَّهِ بْنِ الصَّامِتِ، عَنْ أَبِي ذَرٍّ، أَنَّهُ انْتَهَى إِلَى الرَّبَذَةِ وَقَدْ أُقِيمَتِ الصَّلاَةُ فَإِذَا عَبْدٌ يَؤُمُّهُمْ فَقِيلَ هَذَا أَبُو ذَرٍّ ‏.‏ فَذَهَبَ يَتَأَخَّرُ فَقَالَ أَبُو ذَرٍّ أَوْصَانِي خَلِيلِي صلى الله عليه وسلم أَنْ أَسْمَعَ وَأُطِيعَ وَإِنْ كَانَ عَبْدًا حَبَشِيًّا مُجَدَّعَ الأَطْرَافِ ‏.‏

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 (PBUH)) told me to listen and obey, even if (theleaderwas) an Ethiopian slave with amputated limbs.” Translation Not Available

Book Ref: Sunan Ibn Majah Book 24 Hadith 2862
Web Ref:  Sunan Ibn Majah Vol 4 Book 24 Hadith 2862