The reciter: The author (may Allah have mercy on him) quoted:
"From al-'Abd al-Rahman ibn Sariyah (may Allah be pleased with him), who said: The Messenger of Allah (peace and blessings be upon him) delivered to us a forceful sermon that moved our hearts and caused our eyes to weep. We said: O Messenger of Allah, this is like the sermon of one who is about to depart, so give us advice. He said: I advise you to fear Allah, and to listen and obey, even if a black slave is appointed over you. And whoever among you outlives me will see much disagreement. So hold fast to my Sunnah and the Sunnah of the Rightly Guided Caliphs, and cling to them with your teeth. And beware of newly invented matters, for every religious innovation is misguidance.
وعظنا رسول الله صلى الله عليه وسلم موعظة بليغة وجلت منها القلوب وذرفت منها العيون، فقلنا: يا رسول الله كأنها موعظة مودع فأوصنا، قال: أوصيكم بتقوى الله والسمع والطاعة وإن تأمر عليكم عبد حبشي، وإنه من يعش منكم فسيرى اختلافًا كثيرًا، فعليكم بسنتي وسنة الخلفاء الراشدين المهديين عضوا عليها بالنواجذ، وإياكم ومحدثات الأمور فإن كل بدعة ضلالة
Abu Dawud and al-Tirmidhi narrated it, and he said: It is a good, authentic hadith".