Ahl al-Bayt (, ) refers to the family of the Islamic prophet Muhammad, but the term has also been extended in Sunni Islam to all descendants of the Banu Hashim (Muhammad's clan) and even to all Muslims. In Shia Islam, the term is limited to Muhammad, his daughter Fatima, his cousin and son-in-law Ali ibn Abi Talib, and their two sons, Ḥasan and Husayn. A common Sunni view adds the wives of Muhammad to these five.
While all Muslims revere the Ahl al-Bayt, it is the Shia Muslims who hold the Ahl al-Bayt in the highest esteem, regarding them as the rightful leaders of the Muslim community after Muhammad. The Twelver Shias also believe in the redemptive power of the pain and martyrdom endured by the members of the Ahl al-Bayt, particularly Husayn.
Definition
When () appears in construction with a person, it refers to his blood relatives. However, the word also acquires wider meanings with other nouns. In particular, () is translated as 'habitation' and 'dwelling', and thus the basic translation of is '(the) inhabitants of the house'. That is, literally translates to '(the) people of the house'. In the absence of the definite article , the literal translation of is 'household'.
Other prophets
The phrase appears three times in the Quran, the central religious text of Islam, in relation to Abraham (11:73), Moses (28:12), and Muhammad (33:33). For Abraham and Moses, in the Quran is unanimously interpreted as family. Yet merit is also a criterion of membership in a prophet's family in the Quran. That is, pagan or disloyal members of the families of the past prophets are not excluded from God's punishment. In particular, Noah's family is saved from the deluge, except his wife and one of his sons, about whom Noah's plea was rejected according to verse 11:46, "O Noah, he [your son] is not of your family ()." Families of the past prophets are often given a prominent role in the Quran. Therein, their kin are selected by God as the spiritual and material heirs to the prophets.
Muhammad
The household of Muhammad, often referred to as the Ahl al-Bayt, appear in verse 33:33 of the Quran, also known as the verse of purification. The last passage of the verse of purification reads, "God only desires to remove defilement from you, O , and to purify you completely." Muslims disagree as to who belongs to Muhammad's and what privileges or responsibilities they have.
Inclusion of the Ahl al-Kisa
The majority of the traditions quoted by the Sunni exegete al-Tabari () identify the Ahl al-Bayt with the Ahl al-Kisa, namely, Muhammad, his daughter Fatima, her husband Ali, and their two sons, Hasan and Husayn. Such reports are also cited in , , , all canonical Sunni collections of hadith, and by some other Sunni authorities, including al-Suyuti (), al-Hafiz al-Kabir, al-Hakim al-Nishapuri (), and Ibn Kathir ().
In possibly the earliest version of the hadith of the , Muhammad's wife Umm Salama relates that he gathered Ali, Fatima, Hasan, and Husayn under his cloak and prayed, "O God, these are my and my closest family members; remove defilement from them and purify them completely." Some accounts continue that Umm Salama then asked Muhammad, "Am I with thee, O Messenger of God?" but received the negative response, "Thou shalt obtain good. Thou shalt obtain good." Among others, such reports are given in , , and by Ibn Kathir, al-Suyuti, and the Shia exegete Muhammad H. Tabatabai (). Yet another Sunni version of this hadith appends Umm Salama to the Ahl al-Bayt. In another Sunni version, Muhammad's servant Wathila bint al-Asqa' is also counted in the Ahl al-Bayt.
Elsewhere in , Muhammad is said to have recited the last passage in the verse of purification every morning when he passed by Fatima's house to remind her household of the morning prayer. In his () with a delegation of Najrani Christians, Muhammad is also believed to have gathered the above four under his cloak and referred to them as his , according to Shia and some Sunni sources, including and . This makeup of the Ahl al-Bayt is echoed by the Islamicist Laura Veccia Vaglieri (), and also reported unanimously in Shia sources. In Shia theology works, the Ahl al-Bayt often also includes the remaining Shia imams. The term is sometimes loosely applied in Shia writings to all descendants of Ali and Fatima.