“Listen and obey, even if the one appointed over you is an Ethiopian slave with a head like a raisin.” (Using translation from Ibn Mājah 2860)
قَالَ رَسُولُ اللهِ ﷺ اسْمَعُوا وَأَطِيعُوا وَإِنْ اسْتُعْمِلَ عَلَيْكُمْ حَبَشِيٌّ كَأَنَّ رَأْسَهُ زَبِيبَةٌ