جامع الترمذي

Narrated Umm Al-Husain Al-Ahmasiyyah:

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.'"

[Abu 'Eisa said:] There are narrations on this topic from Abu Hurairah and 'Irbad bin Sariyah. This Hadith is Hasan Sahih, it has been reported through other routes from Umm Husain.