I heard the Messenger of Allah ﷺ delivering Khutbah during the farewell Hajj, and he was wearing a Burd which he had wrapped from under his armpit." She said: "I was look at muscle of his upper arm quivering and I heard him saying: O you people! Have Taqwa of Allah. If a mutilated Ethiopian slave is put in command over you, then listen to him and obey him, as long as he upholds the Book of Allah among you.'" (Using translation from Tirmidhī 1706)
رَأَيْتُ النَّبِيَّ ﷺ وَعَلَيْهِ بُرْدَةٌ قَدِ الْتَفَعَ بِهِ تَحْتَ إِبْطِهِ كَأَنِّي أَنْظُرُ إِلَى عَضَلَةِ عَضُدِهِ تَرْتَجُّ فَسَمِعْتُهُ يَقُولُ «يَا أَيُّهَا النَّاسُ اتَّقُوا اللَّهَ وَإِنْ أُمِّرَ عَلَيْكُمْ عَبْدٌ حَبَشِيٌّ فَاسْمَعُوا لَهُ وَأَطِيعُوا مَا أَقَامَ لَكُمْ كِتَابَ اللَّهِ ﷻ»