It was narrated from 'Abdur-Rahman bin 'Amr As-Sulami that:
He heard Al-'Irbad bin Sariyah say: "The Messenger of Allah (ﷺ) delivered a moving speech to us which made our eyes flow with tears and made our hearts melt. We said: 'O Messenger of Allah. This is a speech of farewell. What did you enjoin upon us?' He said: 'I am leaving you upon a (path of) brightness whose night is like its day. No one will deviate from it after I am gone but one who is doomed. Whoever among you lives will see great conflict. I urge you to adhere to what you know of my Sunnah and the path of the Rightly-Guided Caliphs, and cling stubbornly to it. And you must obey, even if (your leader is) an Abyssinian leader. For the true believer is like a camel with a ring in its nose; wherever it is driven, it complies."
حَدَّثَنَا إِسْمَاعِيلُ بْنُ بِشْرِ بْنِ مَنْصُورٍ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ السَّوَّاقُ، قَالاَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، عَنْ مُعَاوِيَةَ بْنِ صَالِحٍ، عَنْ ضَمْرَةَ بْنِ حَبِيبٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَمْرٍو السَّلَمِيِّ، أَنَّهُ سَمِعَ الْعِرْبَاضَ بْنَ سَارِيَةَ، يَقُولُ وَعَظَنَا رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ مَوْعِظَةً ذَرَفَتْ مِنْهَا الْعُيُونُ وَوَجِلَتْ مِنْهَا الْقُلُوبُ فَقُلْنَا يَا رَسُولَ اللَّهِ إِنَّ هَذِهِ لَمَوْعِظَةُ مُوَدِّعٍ فَمَاذَا تَعْهَدُ إِلَيْنَا قَالَ ‏ "‏ قَدْ تَرَكْتُكُمْ عَلَى الْبَيْضَاءِ لَيْلُهَا كَنَهَارِهَا لاَ يَزِيغُ عَنْهَا بَعْدِي إِلاَّ هَالِكٌ مَنْ يَعِشْ مِنْكُمْ فَسَيَرَى اخْتِلاَفًا كَثِيرًا فَعَلَيْكُمْ بِمَا عَرَفْتُمْ مِنْ سُنَّتِي وَسُنَّةِ الْخُلَفَاءِ الرَّاشِدِينَ الْمَهْدِيِّينَ عَضُّوا عَلَيْهَا بِالنَّوَاجِذِ وَعَلَيْكُمْ بِالطَّاعَةِ وَإِنْ عَبْدًا حَبَشِيًّا فَإِنَّمَا الْمُؤْمِنُ كَالْجَمَلِ الأَنِفِ حَيْثُمَا قِيدَ انْقَادَ ‏"‏ ‏.‏
GradeSahih (Darussalam)
English reference : Vol. 1, Book 1, Hadith 43
Arabic reference : Book 1, Hadith 45