Islam is comprised of two divine sources: Qur’an, and Hadith.

The speech, actions, and teachings of the prophet (saw) have been meticulously preserved by scholars of hadith upholding the highest of academic standards. Each and every potential hadith must be tested and verified through the most rigorous authentication process before it can be declared sound and authentic.

A key step in the process of verification is the topic of ‘ilal al-ḥadīth – hidden defects within hadith. These defects could either occur within the text itself (matn) or the chain of narration (sanad).

Throughout the history of Islam, scholars who specialise in authenticating hadith have sought to preserve the Sunnah of the Prophet (saw) and distinguish that which is authentically attributed to him to that which is not.

Imam Muslim is of the foremost scholars of Hadith, and his works are studied and relied upon for over 1,000 years after his time until today. Kitāb al-Tamyīz is one of his most important works, serving as an indispensable tool in the science of Hadith.