حَدَّثَنَا مُحَمَّدُ بْنُ يَحْيَى النَّيْسَابُورِيُّ، حَدَّثَنَا مُحَمَّدُ بْنُ يُوسُفَ، حَدَّثَنَا يُونُسُ بْنُ أَبِي إِسْحَاقَ، عَنِ الْعَيْزَارِ بْنِ حُرَيْثٍ، عَنْ أُمِّ الْحُصَيْنِ الأَحْمَسِيَّةِ، قَالَتْ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَخْطُبُ فِي حَجَّةِ الْوَدَاعِ وَعَلَيْهِ بُرْدٌ قَدِ الْتَفَعَ بِهِ مِنْ تَحْتِ إِبْطِهِ قَالَتْ فَأَنَا أَنْظُرُ إِلَى عَضَلَةِ عَضُدِهِ تَرْتَجُّ سَمِعْتُهُ يَقُولُ ‏"‏ يَا أَيُّهَا النَّاسُ اتَّقُوا اللَّهَ وَإِنْ أُمِّرَ عَلَيْكُمْ عَبْدٌ حَبَشِيٌّ مُجَدَّعٌ فَاسْمَعُوا لَهُ وَأَطِيعُوا مَا أَقَامَ لَكُمْ كِتَابَ اللَّهِ ‏"‏ ‏.‏ قَالَ أَبُو عِيسَى وَفِي الْبَابِ عَنْ أَبِي هُرَيْرَةَ وَعِرْبَاضِ بْنِ سَارِيَةَ ‏.‏ وَهَذَا حَدِيثٌ حَسَنٌ صَحِيحٌ وَقَدْ رُوِيَ مِنْ غَيْرِ وَجْهٍ عَنْ أُمِّ حُصَيْنٍ ‏.‏

Narrated Umm Al-Husain Al-Ahmasiyyah: I heard the Messenger of Allah (PBUH) 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. Translation Not Available

Book reference: Jamiya Tirmidhi Book 23 Hadith 1706
Web reference: Jamiya Tirmidhi Volume 3 Book 21 Hadith 1706