I hear Muslims (all the damn time) debate about this issue, so unnecessarily. So, what I’ve decided to do is the following: do some actual, honest, unbiased, historically true, research as to who the Ahl-ul-Bayt truly are. And, once you embark upon this type of research, you’ll learn so much about the actual Ahl-ul-Bayt, as well as significant aspects of Islam, generally, historically, and, as to why people have been at odds over this one singular issue, for so many centuries.
So, without any further adieu, here’s what I’ve got:
Ahl-ul-Bayt (literally meaning, “The People of the House”, referring to the Prophetic-Household of Muhammad [Peace be upon him]) isn’t just a group of four persons (Fatimah, `Ali, al-Hasan & al-Husayn [May Allah be pleased with them]), and their familial-descendants. Rather, Ahl-al-Bayt, based upon its strongest Islamic understanding, according to as-Salaf (as-Sahabah/the Companions of Muhammad [May Allah be pleased with them altogether] & generations 1 & 2 of at-Tabi`in/the followers of as-Sahabah [May Allah mercify them altogether]), are persons whom were Muslims, during the lifetime of Muhammad (Peace be upon him) & were either related to him through blood or through marriage.
Ahl-al-Bayt are specifically categorized as 3-Tier categories:
The actual blood-relatives, both paternal & maternal, of Muhammad, who became Muslims during his own lifetime-Among them are, but not limited to, the following: `Abbas/al-`Abbas ibn-`Abd-il-Muttalib, Hamzah ibn-`Abd-il-Muttalib, Harith/al-Harith ibn `Abd-il-Mutalib (all of them were Paternal-Uncles of Muhammad, the brothers of his father, `Abdullah ibn `Abd-il-Muttalib), `Abdullah ibn-`Abbas, Fadhl ibn-`Abbas, `Ali ibn Abi-Talib, Ja`far ibn Abi-Talib,`Aqil ibn Abi-Talib, `Ubaydah ibn-il-Harith (the first Companion of Muhammad to be killed in battle [the Battle of Badr]), Rabi`ah ibn-il-Harith, Abu-Sufyan ibn-il-Harith (both of whom were among 8-persons whom did not flee during the Battle of Hunayn), Arwah bint-il-Harith, Hind bint Abi-Umayyah & Zaynab bint-Jash (who were both cousins of Muhammad & two of his wives), Waraqah ibn-Nawfal (the Christian-Priest, who died as a Muslim & Companion, on account of him believing in the legitimacy of the Prophethood of Muhammad [a paternal-cousin of Khadijah bint-Khuwaylid, the 1st wife of Muhammad]), etc. This has actually been proven, through a Hadith/Narration of Muhammad in which he was specifically asked, “Who are Ahl-ul-Bayt?”. Muhammad had mentioned that, “Ahl-ul-Bayt are persons whom Zakah (not Saqaqah/Optional-Charity, but the annual Zakah/Obligatory-Charity) is Mahrum for (meaning that it is Islamically-Prohibited for them to be recipients of it). From among them are: `Abbas (ibn `Abd-il-Muttalib) & the descendants of `Abbas, `Ali (ibn Abi-Talib) & the descendants of `Ali, Ja`far (ibn Abi-Talib) & the descendants of Ja`far, and `Aqil (ibn Abi-Talib) & the descendants of `Aqil.”.(Muslim) In addition to this: it’s important to note that all of al-`Asharat-ul-Mubashshirin (the 10-Companions of Muhammad [Peace be upon him] who were promised Paradise in their lifetimes, by name) were all in fact blood-related to Muhammad via their Common-Ancestor `Abd-Manaf.(ar-Rahiq-ul-Makhtum, Hayat-us-Sahabah)
The Wives of Muhammad, the Mothers of the Believers and his In-Laws (Relatives via Marriage)-We know, for a fact, that these women are among Ahl-il-Bayt, just because, in Surat-il-Ahzab/the Chapter of the Partisans (Chpt.3, V.61 & Chpt.33, V.33), Allah mentions the Wives of Muhammad, as a group, and gives them the honorable title, “Ahl-ul-Bayt”. And, among his In-Laws are, but not limited to, the following: `Abdullah ibn Abi-Quhafah/Abu-Bakr as-Siddiq (father-in-law), `Umar ibn-ul-Khattab (father-in-law), `Uthman ibn-`Affan (son-in-law), `Ali ibn Abi-Talib (son-in-law), Abu-Sufyan ibn-Harb (father-in-law), Hind bint-`Utbah (mother-in-law), Yazid ibn Abi-Sufyan (the brother of Mu`awiyah whom also accepted Islam [brother-in-law]) Hudhayfah ibn-`Utbah (uncle-in-law), Mu`awiyah ibn Abi-Sufyan (brother-in-law), Yazid ibn-Mu`awiyah (nephew-in-law), etc.(ar-Rahiq-ul-Makhtum/The Sealed-Nectar)
The Children & Grand-Children, Step-Children & Adopted-Children of Muhammad-Among the Children of Muhammad are the following: Fatimah, Ruqayyah, Zaynab, Umm-Kulthum, `Abdullah, al-Qasim, Ibrahim-Among his Grand-Children are, but not limited to, the following: al-Hasan ibn-`Ali, al-Husayn ibn-`Ali, Among his Step-Children are, but not limited to, the following: `Umar ibn Abi-Salamah (his mother, Hind bint Abi-Umayyah, had married Muhammad, after his father, `Abdallah ibn-`Abd-il-Asad, had been martyred during the Battle of Uhud), Sakran ibn-is-Sakran ibn`Amr (his mother, Sawda’ bint-Zam`ah had married Muhammad, after her husband, as-Sakran ibn`Amr ibn `Abd-ish-Shams had died when on route to al-Madinah, from the 1st-Hijrah, from al-Makkah, to Abyssinia), etc. The Adoptive-Children of Muhammad were only Zayd ibn-il-Harithah.(ar-Rahiq-ul-Makhtum)
Now, as we can all clearly see, there are at the very least, up to about 50 individuals, who can easily be classified as Ahl-al-Bayt, just from the names of persons whom I’ve already mentioned. Now, with that being said, for someone to say that they “only take knowledge from members of Ahl-il-Bayt”, or that they “prefer to only take from Ahl-il-Bayt”, or that they “trust Ahl-al-Bayt more”, then, they will seriously have to change their perspectives on a lot of individuals, because most of the individuals whom I’ve mentioned most-definitely have the most-rightful claims to being from among Ahl-il-Bayt, yet among certain sectarian-groups, they’re just not acknowledged as such.
And, also, when you observe/study the authentic narrations in which the names of any, some, most of these persons are mentioned in, you find that not only are those narrations are classified as Sahih/Authentic, by the vast majority of well-known/well-trusted Hadith-Scholars, from among the Salaf, but that these same narrations can be & are found within some of the most highly-regarded & respected collections of Prophetic-Statements. And, more importantly, these same persons, most of them, those who could read & write, were in fact persons, trusted & commissioned by Muhammad to document not only the Qur’an itself, but also Prophetic-Statements.
So, with that being said, it’s pretty clear that Ahl-al-Bayt is so much more extensive, than most people give it credit for.