The Book of Judicial Decisions - Sahih Muslim 1718a

He who innovates things in our affairs for which there is no valid (reason) (commits sin) and these are to be rejected.

Commentary on the Hadith

This noble hadith establishes a fundamental principle in Islamic law: every innovation in religious matters that lacks legitimate basis from the Quran or Sunnah is rejected. The phrase "our affairs" refers specifically to matters of religion and worship, not worldly innovations.

Scholars distinguish between two types of innovation: blameworthy innovation (bid'ah sayyi'ah) in religious matters and praiseworthy innovation (bid'ah hasanah) in worldly matters. The prohibition here applies exclusively to introducing new practices in worship that contradict established Islamic principles.

The phrase "to be rejected" indicates such innovations hold no legal weight and bring no reward, even if performed with good intention. This protection preserves the purity of Islamic worship from human alteration.

Legal Implications

This hadith serves as a primary source for the principle of blocking the means to evil (sadd al-dhara'i). It prevents gradual corruption of religion through seemingly minor deviations that may lead to major innovations.

The ruling applies equally to adding to worship what is not part of it or subtracting from it what is essential. Both constitute unacceptable innovation when done without divine authorization.