Ghusl in the context of "Ihram"

Hadith sciences (Arabic: علم الحديث ʻilm al-ḥadīth "science of hadith") consists of several religious scholarly disciplines used by Muslim scholars in the study and evaluation of the hadith. ("Science" is used in the sense of a field of study, not to be confused with following the principles of observation and experiment, developing falsifiable hypotheses, etc. of modern science.) The hadith are what most Muslims believe to be a record of the words, actions, and silent approvals of the Islamic prophet Muhammad as transmitted through chains of narrators. Hadith science scholars aim to determine which of these records are authentic, and which may be fabricated.

For most Muslims, determining the authenticity of hadith is enormously important in Islam because along with the Quran, the Sunnah of the Islamic prophet—his words, actions, and silent approvals—are considered the explanation of the divine revelation (wahy), and the record of them (i.e. hadith) provides the basis of Islamic law (Sharia). In addition, while the number of verses pertaining to law in the Quran is relatively few, hadith, for many, give direction on everything from details of religious obligations (such as Ghusl or Wudu, ablutions for salat prayer), to the correct forms of salutations, to the importance of benevolence to servants. Thus, the "great bulk" of the rules of Islamic law are derived from hadith, along with the Quran as a primary source.

Purity (Arabic: طهارة, romanized: ṭahārah) is an essential aspect of Islam. It is the opposite of najāsa, the state of being ritually impure. It is achieved by first removing physical impurities (for example, urine) from the body, and then removing ritual impurity through wudu (usually) or ghusl.