He would also say in his sermons: “The worst matters are newly introduced ones, and every innovation is misguidance.”

Ibn Masʿūd would deliver a similar sermon every Thursday, saying: “You will introduce new things, and new things will arise for you.”

We have already established in al-Qawāʿid (The Principles), under the principle concerning the Sunnah and innovation, that innovation is religion that Allah and His Messenger have not commanded. Whoever adopts a religious practice that Allah and His Messenger have not commanded is thereby an innovator. This is the meaning of Allah Most High’s words:

“Or do they have partners who have ordained for them in religion what Allah has not permitted?”
[Surah al-Shūrā 21]

Undoubtedly, many people find this difficult to understand because they lack knowledge of the scriptural texts and how they indicate the intended meanings. They also lack knowledge of the opinions and practices that have been introduced, and how to refer these back to the Sunnah. As ʿUmar ibn al-Khattāb said: “Refer matters of which you are ignorant back to the Sunnah.”