سنن ابن ماجه

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."