The term "ahl" signifies the members of a household of a man,including his fellow tribesmen, kin, relatives, wife (or wives), children, and all those who share a family background, religion, housing, city, and country with him.
"Ahl" and "al" are both the same term with the exception that "al" is exclusively used for human beings and should come before the family name, but such a condition is not existent in the case of "ahl". "Bayt" refers to habitation and dwelling, including tents and buildings both. The "ahl-al-bayt" of any person refers to his family members and all those who live in his house (c.f. "Mufradat al-Qur'an"
The term "ahl-al-bayt" (people of the house) has been repeated twice in the Holy Qur'an: The mercy of Allah and his blessing are on you, O people of the house, ... (11:73)"
This verse refers to the people of the House of Ibrahim (s)
2. Allah only desires to keep away the uncleanness from you, O people of the House! And to purify you a(thorough) purifying (33:33)".
This verse, known as the "Tathir verse", refers to the Members of the Household of the Holy Prophet (s). The Imamiyyah scholars of hadith and fiqh, as well as some Sunni `Ulama, consider the "ahl-al-bayt" cited in the "tathir verse" to include exclusively Muhammad, `Ali, Fatimah, Hasan, and Husayn (peace be upon them all). They do not consider the Holy Prophet's other offspring, wives, sons of paternal uncles, and dwellers of his house as the Messenger's "ahl-al-bayt".
