If any one introduces into this affair of ours anything which does not belong to it, it is rejected. Ibn `Isa said: The Prophet (ﷺ) said: If anyone practices any action in a way other than our practice, it is rejected.
Sunan Abi Dawud Book 42, Hadith 11
← Previous Hadith The Prophet (ﷺ) said: Let me not find one of you reclining on his couch when he hears something regarding me which I have commanded or forbidden and saying: We do not know. What we found in Allah's Book we have followed.

Sunan Abi Dawud Book 42, Hadith 10 Next Hadith → AbdurRahman ibn Amr as-Sulami and Hujr ibn Hujr said: We came to Irbad ibn Sariyah who was among those about whom the following verse was revealed: "Nor (is there blame) on those who come to thee to be provided with mounts, and when thou saidst: "I can find no mounts for you."

We greeted him and said: We have come to see you to give healing and obtain benefit from you.

Al-Irbad said: One day the Messenger of Allah (ﷺ) led us in prayer, then faced us and gave us a lengthy exhortation at which the eyes shed tears and the hearts were afraid.

A man said: Messenger of Allah! It seems as if it were a farewell exhortation, so what injunction do you give us?

He then said: I enjoin you to fear Allah, and to hear and obey even if it be an Abyssinian slave, for those of you who live after me will see great disagreement. You must then follow my sunnah and that of the rightly-guided caliphs. Hold to it and stick fast to it. Avoid novelties, for every novelty is an innovation, and every innovation is an error.

Sunan Abi Dawud Book 42, Hadith 12