A core theological question within Islam revolves around the authoritative sources of religious law and guidance. While the majority of Muslims rely on two sources—the Koran and the Hadith (sayings and actions attributed to the Prophet Muhammad)—a powerful counter-argument holds that the Koran alone is the complete, sufficient, and only divinely authorized scripture. This position rests on the assertion that elevating any secondary source fundamentally undermines the Koran's own definitive claims and introduces profound theological and practical inconsistencies.
The most direct challenge to the Hadith tradition comes from the Koran's explicit claims of completeness and perfect detail. The text repeatedly affirms its status as the singular source of truth, guidance, and law, calling itself fully detailed and a clear light. It directly challenges the reader, in verses like Surah Al-Jathiyah 45:6, with the question: "In what other discourse after God and His verses do they believe?" This direct Koranic interrogation, which asserts the scripture’s perfection upon its delivery, outright dismisses the necessity of any supplemental textual authority. If the divine law is complete and easy to understand, as the Koran claims, the subsequent creation of a massive, complex, and often contradictory secondary body of work—the Hadith—is rendered redundant.
Furthermore, the Hadith collection suffers from an inherent fatal flaw in its process of human transmission. Collected and codified two to three centuries after the Prophet’s death, this literature is vulnerable to the same issues that plague all ancient oral traditions—the phenomenon popularly known as Chinese whispers. Despite the scholarly attempts to verify authenticity through the isnad (chain of narration), the sheer volume of admitted fabrications and the necessity for scholars to be selective about which Hadiths are deemed authentic already betrays the system’s lack of divine infallibility. The requirement to filter the sound from the spurious is a human attempt to impose order on inherently flawed sources, starkly contrasting with the universally acknowledged, preserved purity of the Koran.
From a theological standpoint, relying on any source besides the Koran introduces the grave concepts of bid’ah (innovation) and shirk (associating partners with God). The act of legislating religious practice based on unverified, humanly preserved accounts is considered a dangerous bid’ah, or heretical innovation, as it implies the religion was somehow incomplete upon its final revelation. More critically, when these traditions are given an authority co-equal to God’s word, it becomes a form of shirk, or polytheism in authority, creating a dual source of law where the Koran intended only one. The singular, clear path of the Koran is thus obscured by a dense layer of human interpretation and historical baggage, which, ironically, often fuels the very extremism and sectarianism the scripture warns against. The path to religious purity and unity, therefore, lies in recognizing the Koran as the final and only definitive guide.