What is a Hadith? It is an account of reported actions, words and or approval of certain action attributed to Prophet Muhammad. Hadiths are an accumulation of actions, advice and commandments of the prophet passed on through the word of mouth and compiled about 200 years after the death of the prophet.
The biggest criticism on the hadiths is on their authenticity, whether they were the actual words and actions of the prophet, the reliability of the transmitters, their character and memory.
A sizable majority of Muslims disagree on using hadiths as a source of Islamic law.
"Deniers of Hadiths" question whether the hadith can provide rulings on legal and religious matters when the Quran has already declared itself "complete", "clear", "fully detailed" and "perfected". Also, some scholars contend that the Quran itself has forbidden using extra-Quranic literature for guidance while obeying the prophet by following his commandments.
Among the scholars, some believed that even Sahih hadith suffer from corruption and proposed limitations on the usage of hadith. They are the early Muslims Al-Nazzam (775–845), Ibn Sa'd (784–845), Al-Nawawi (1233–1277), Ibn Hajar (1372–1449), later reformers Syed Ahmed Khan (1817–1898), and Muhammad Iqbal(1877–1938), and the Western scholars, such as Ignác Goldziher, Joseph Schacht, and G.H.A. Juynboll.
According to Bernard Lewis, "in the early Islamic centuries, there could be no better way of promoting a cause, an opinion, or a faction than to cite an appropriate action or utterance of the Prophet." This gave a strong incentive to fabricate hadith.
Experts, in general, have estimated the number of full-isnad narration at 7,397, and without considerations to repetitions or different versions of the same report, the number of Prophetic traditions reduces to approximately 2,602.
According to Daniel Brown, the major causes of the corruption of Hadith literature are:
• Political conflicts,
• Sectarian prejudice, and
• The desire to translate the underlying meaning, rather than the original words verbatim.
Other criticisms on hadiths are:
• That hadiths cannot be used as a major source of Islamic law involving the honour, property and lives of Muslims. Although Sahih hadith are defined as "authentic", above Hasan (good) and Daif (weak) hadith—this class of hadith do not provide "certainty of knowledge" needed for lawmaking.
• Mutawatir hadith, meaning reports from "a large number of narrators whose agreement upon a lie is inconceivable", do meet the criteria of authenticity but their extreme scarcity limits their use in the development of Islamic law.
• The orthodox tool of Hadith verification is through the chain of transmitters. However, they are all subject to corruption by faulty memory or manipulation.