Several hadith indicate the importance as sources of Islam not only the Quran, but also of the Sunnah. One of these hadith quotes Muhammad as saying : Sunni Muslims generally accept this hadith as authentic ; whereasShi'a Muslims reject it as fabricated or inauthentic.
Background
explains the importance of the Quran and the Sunnah in Islam: "the Prophet Muhammad is seen as the 'living Quran,' the embodiment of God's will in his behavior and words. Sunni Muslims... take their name from sunnah, meaning those who follow the example of the Prophet." Prof. Fatih Okumus refers to Muhammad as "the walking Qur’an," with the Sunnah giving an example to follow. Both Sunni and Shia Muslims agree on the general importance of following both the Quran and the Sunnah. However, they may disagree as to whether some hadith or tradition forms part of the Sunnah in the first place. As the sayings and deeds of Muhammad were reported via many different sources, there was disagreement about what constituted sunnah, and how that affects what should be shariah.
Both Sunni and Shi'a Muslims accept the authenticity of the similar hadith of the two weighty things : The Hadith al-Thaqalayn holds special importance for Shi'a Muslims, because they perceive it to provide support for the succession of Ali rather than Abu Bakr. Shi'as view the Hadith al-Thaqalayn as a clear indication that Muhammad wished to keep the matter of leadership within his own family. It is based on this claim that the Shi'as reject the first three Sunni caliphs. Sunnis, by contrast, recognize the Hadith al-Thaqalayn as sahih but see it as mandating respectful obedience to members of the Ahl al-Bayt, rather than pertaining to succession.
Sunni view
The hadith of the Quran and Sunnah appears in the Muwatta Imam Malik, often identified as one of the six most authentic books of hadith in the Sunni tradition. Versions of this hadith are cited in many Sunni collections. Among these are:
This hadith is considered sahih by the following Sunni scholars:
Hakim al-Nishaburi
Ibn Abd al-Barr
Ibn Hazm
The Sunnis generally accept this hadith, but narrowly define sunnah as the sayings and deeds of Muhammad. From a Sunni viewpoint, the Shi'a definition of sunnah is too broad; it includes Muhammad's "implicit approvals" and even the sayings of imams other than Muhammad.
In the ninth centuryAl-Shafi‘i took the view that the Quran superseded sunnah, and that sunnah could not supersede the text of the Quran. In this he rejected versions of the above hadith which claimedequal weight for the Quran and the Sunnah. Others, notably Ibn Kathir in his book Al-Bidaya wa'l-Nihaya, took the reverse position that sunnah, being a later revelation, should take precedence over the Quran.
Shi'as reject the hadith of the Quran and Sunnah, deeming it to be a fabrication designed to distract from another saying of Muhammad — the Hadith al-Thaqalayn — by replacing the latter's specific and pointed reference to Muhammad's Ahl al-Bayt with a generic reference to the sunnah. The Shi'as believe that the Hadith al-Thaqalayn is mutawattir, meaning that it has been related so many times by so many people that there is no doubt about its authenticity.
