Shirk

Associating partners with Allah — the gravest of all the major sins and the only one the Quran describes as an unforgivable wrong if a person dies in that state without repentance: 'Allah does not forgive shirk being associated with Him, but He forgives less than that to whom He wills' (4:48). Al-Dhahabi begins his catalogue with shirk because everything else is ranked below it. He distinguishes the major shirk — ascribing partners, equals, or rivals to Allah — from the minor shirk of showing off (riya'), which the Prophet described as the thing he feared most for his community. Understanding the categories of shirk is the foundation of understanding all that follows in the book.

As understood in the classical tradition of Imam al-Dhahabī and the scholars of his school.