The Prophet ﷺ said to Abu-Dhar, "Listen and obey (your chief) even if he is an Ethiopian with a head like a raisin." (Using translation from Bukhārī 696)

أَنَّ رَسُولَ اللهِ ﷺ قَالَ لِأَبِي ذَرٍّ اسْمَعْ وَأَطِعْ وَلَوْ لِحَبَشِيٍّ كَأَنَّ رَأْسَهُ زَبِيبَةٌ