The hadith is the collected oral tradition about Muhammad—tradition that is crucial in shaping the beliefs of Muslims. In Islam, the primary holy text is the Qur’an, which Muslims believe was dictated to Muhammad by the supreme deity, Allah. This revelation is relatively short on detail. For all intents and purposes, Islamic doctrines are more robustly sourced in the hadith than anywhere else. These traditions, in reference to the Qur’an, form the basis of most Islamic doctrine and practice.
The Bible and the Qur’an are nothing alike in form, history, style, or their place in their respective religions. Unlike most of the Bible, the Qur’an is not linear or topical. Rather, it is a collected series of separate statements. The chapters are not in chronological order. Even more confusing is that these statements are not given broader context within the Qur’an itself; they are mostly the dictations of Muhammad, nothing more. The Qur’an is also significantly shorter than the Bible, about two-thirds the length of the New Testament. This means there is much less context available for interpretation. Beyond this, Muslims claim the Qur’an can only be properly understood in its original language, so those unfamiliar with that dialect are unable to truly read it.
Those factors oblige extensive explanation in order to apply the Qur’an. After Muhammad’s death, Islamic scholars collected records of comments made by those who had interacted with him. These especially included his wives and military generals. Whereas the Qur’an supposedly contains direct quotations made by Muhammad on behalf of Allah, the hadith is composed of memories about Muhammad’s opinions and behavior, as retained by his associates.
As one would expect, there are an enormous number of memories put forward by Muhammad’s friends and family. Some of the accounts differ or even contradict each other. Islamic scholars have categorized the traditions contained in the hadith by how well-supported they are. Muslims give special preference to traditions with an unbroken chain recording how the tradition was passed down. Such analysis is extremely subjective—in fact, different sects of modern Islam are vaguely defined by which hadith they accept or reject. Sunni and Shia Muslims, for example, generally rely on a completely different set of hadith. Even between two individual Muslims, it’s possible to find portions of the hadith to support both sides of a contrary view.
Individual collections of hadiths may contain more than ten thousand separate statements. The two most important and well-respected collections of the hadith are known as Sahih Muslim and Sahih al-Bukari. These are believed to be the most well-attested and reliable records of Muhammad’s associates.
The hadith adds significant complexity to understanding Islamic belief and practice. Despite both being labeled “Abrahamic faiths,” Islam is fundamentally different from Judeo-Christianity. Those differences include the “chain of command” these religions apply when it comes to core doctrinal beliefs. The hadith has been described as the only filter through which Islam can be defined and understood.
In a very coarse sense, one could compare the relative status of the Qur’an and hadith to that of the United States Constitution and the opinions of certain judges. There is a concise fundamental document—the Qur’an / Constitution—that begs more specific interpretation. Different people will have different interpretations—hadith / judicial writings—about the original document’s intent. The original document is the ultimate authority, but, in practice, extensive commentary about the document and its writers shapes the system. This comparison is admittedly flimsy, but it may be helpful to those struggling to understand the different roles the Bible and the Qur’an play in their respective faiths.