The limiting of the Ahlul Bayt (ع) to the fourteen infallibles is not a human decision; it is an exclusivity understood from the Divine words in the Verse of Purification and the traditions of the noble Prophet (ص).
There are numerous discursive and traditional proofs than can be relied on to prove this claim.
Discursive and textual proofs
a. The Qur`an consists of the words of Allah (awj) that He revealed to His Prophet in the Arabic language. And Allah’s (awj) words, like His actions, are free of any sort of defect; it is not possible for them to contain any type of grammatical mistake.
Now, if the term Ahlul Bayt in the Verse of Purification were to refer to all relatives of the Prophet (ص), it would be in violation of the rules of Arabic grammar and detrimental to the eloquence and perfection of the Divine word. This is because the Prophet (ص) had more than fifteen wives and for a masculine pronoun to be used in the Verse of Purification to refer to a group, the majority of which were women, would be contrary to proper ‘Arabic speech. Thus, the pronouns in the verse refer to the descendents and trustees of the Prophet (ص) in the house of Fatima I.
b. To determine the meaning of a word, it is necessary to look at the context in which it originated in order to understand its true exact sense. In the Verse of Purification, the word ahl (family or people) is under discussion. This word must always be in a possessive phrase, at least in meaning if not in words. That is, its meaning is incomplete unless it is attributed or related to something else. In this verse as well it has been attributed to al-bayt, or the house of prophecy; and we know that this can apply to no house aside from that of Fatima I. If al-bayt referred to an inhabited house, for the other wives of the Prophet (ص) to be included in this phrase, Umm Salamah—in whose house the verse was revealed—should be the first person to be included in the phrase. But the opposite is true, since the Prophet (ص)—with Umm Salamah’s agreement—did not consider her to be among the Ahlul Bayt.
Traditional proofs
a. There are a group of traditions in which the Prophet (ص) aimed to clarify and delimit the Ahlul Bayt (ع) in the Verse of Purification. Thus, the Prophet (ص) said that this verse was revealed about five people: himself, ‘Ali, Fatima, Hasan, and Husayn (ع).
b. Another group of traditions that mention the Prophet’s actions in this regard, since practical teachings are more lasting than oral teachings. Thus, it has been narrated that for six months the Prophet (ص) would come to the door of Fatima’s I house at prayer times and say, “Prayers, O People of the House!” and he would recite the Verse of Purification.
c. A third group are the accounts that indicate that it was well-known to the people that the Ahlul Bayt are limited to these people, the details of which have been mentioned in books of Qur`anic exegesis.
To prove that the Ahlul Bayt (ع) in the Verse of Purification are limited to the five “people of the cloak” (ahl al-kisa’: the Prophet, ‘Ali, Fatimah, Hasan, and Husayn, upon whom be peace), various textual and traditional proofs that are accepted by Sunnis and Shi’as can be forwarded. We will look at each of these proofs separately.
Discursive or Textual Proofs
a. The Qur`an is the word of Allah (awj) and is a miracle from more than just a single aspect. The most accessible and easily grasped of those aspects is the Qur`an’s eloquence.
That is, there exists no literary mistake in the matter, style, or choice of wording of the Noble Book. We know that in ‘Arabic there are separate feminine pronouns used in the second and third persons. In using a pronoun, numerous aspects are taken into account. For example, when there are significantly more women in a group than men, a feminine pronoun is used.
Now, if a masculine pronoun were to be used in addressing a group consisting primarily of women, it would be considered a grammatical mistake. If a person uses masculine pronouns in place of feminine ones or vice versa, it would be an amusing mistake. Far be it from the Qur`an, the Word of Allah and the Prophet’s (ص) eternal miracle, to make such a mistake.
The Verse of Purification has the words ‘ankum and yutahhirakum, in which the pronouns are masculine, though Allah (awj) is well aware that there were more women in the Prophet’s household than men. So if we were to hold that this verse refers to all of his household and family, we would have to say that we have found a grammatical mistake in the Qur`an, that is, the use of two masculine pronouns in place of feminine ones—a mistake that is clear and undeniable.
It is obvious that this is inconsistent with the Muslim belief in the Qur`an’s miraculousness and Allah’s (awj) Knowledge and Wisdom, and is thus unacceptable. Thus, the two pronouns must refer to a group that would permit masculine pronouns to be used. And this is only the case if we take the pronouns in the verse to refer to the Prophet’s household in the house of Fatimah, that is, the Prophet, Fatimah, ‘Ali, Hasan, and Husayn (ع).
b. The word ahl (family) in Arabic must always be part of a possessive phrase in meaning. That is, it must be related or attributed to something else for its own meaning to become clear, as in ahl al-kitab (people of the book), ahl al-iman (people of faith, or believers), and ahl al-nifaq (people of hypocrisy, or hypocrites).
Thus part of the meaning of the word ahl is denoted by the word to which it is attributed. So, if we wish to know what ahl means in the Verse of Purification we must first determine the meaning of the word bayt (house).
The word bayt means “house” or “abode” and denotes a place. Now what is meant by this word in different usages is something that is explained by contextual clues, both internal (verbal) and external (nonverbal).
The same holds true for the topic under discussion, that is, the expression “Ahlul Bayt.” So if there are no contextual clues to limit, expand, or clarify what Allah intended with this expression, if we were to ignore the literary objection that would result, it would be possible to take “Ahlul Bayt” to refer to everyone related to the Prophet (ص) in his houses. In this case, the word bayt would mean “home” or “residence”.
But with a little attention to some external contextual clues, such as the situation in which the verse was revealed, we will realize that such a meaning is untrue, because although the verse was revealed in the very house of Umm Salamah, the Prophet (ص) clearly said she was not one of the Ahlul Bayt (ع). If bayt were to refer to a residence, Umm Salamah—in whose home the verse was revealed—should be its first addressee and more worthy of this title than anyone else.
But it has already been shown that this is contrary to reality. In this regard, it would be good to refer to a tradition that Wahidi Nishapuri has narrated:
“Umm Salamah relates that the Prophet (ص) was in [my] house and food was before him when Fatimah (ع) entered. The Prophet (ص) said, ‘[Fatimah,] call your husband and sons to come to me.’ ‘Ali, Hasan, and Husayn (ع) came and sat down. While they were eating, the Prophet (ص) fell asleep.
“There was a Khaybari cloak under the Prophet (ص) during this time, and I was in the [adjoining] room praying. Then Allah revealed the Verse of Purification.
“After this, the Prophet (ص) covered them [‘Ali, Fatimah, Hasan, and Husayn] with his cloak as well. Then he took out his hands and, facing the sky, said: ‘O Allah! These are my Ahlul Bayt and the closest ones to me. Remove from them all uncleanliness and purify them.’
“At that time I came to their room and asked, ‘Am I too with you O Messenger of Allah?’ He replied, ‘You are on the right [path]. You are on the right [path].’”[1]
In this way, the Prophet (ص) praised Umm Salamah without considering her to be one of the Ahlul Bayt.
There are numerous traditions with the above purport in Sunni hadith collections[2]. This is the same tradition that is well-known among Shi’as as the tradition of the cloak (hadith al-Kisa) and which is found in most books of hadith and supplications.
Traditional Proofs
There are numerous traditions that clarify what Allah (awj) meant by Ahlul Bayt in the verse of Purification. In view of the various details and aspects explained in these traditions, we have divided them into three groups and will mention one example from each group. It is worthy of mentioning that only Sunni sources have been used for the following traditions, though comparable traditions are abundant in Shi’a sources as well.
a. The first group consists of traditions that explain the Prophet’s (ص) words regarding the purport of the expression Ahlul Bayt in the verse of Purification.
Muhammad ibn al-Muthanna, with a chain reaching Abu Sa’id al-Khidri, narrates that the Prophet (ص) said, “This verse was revealed regarding five people—me, ‘Ali, Fatimah, Hasan, and Husayn:
‘Verily, Allah only wishes to remove all uncleanliness from you, O people of the house, and purify you thoroughly.’”[3]
b. The second group consists of traditions that came after the meaning of Ahlul Bayt had been explained verbally and that clarify its meaning in actions through the conduct of the Prophet (ص).
Ibn Waki`, in a chain leading to Anas, relates that he would say, “For six months after the Verse of Purification was revealed, whenever the Prophet (ص) would go for prayers, he would stand outside the door of Fatimah’s house and say, ‘[It is time for] the prayers, O people of the house!’ and then he would recite this verse.”[4]
Does this prophetic action, which continued for 180 days, five times a day, in explaining the meaning of Ahlul Bayt leave any room for doubt?
c. The third group consists of traditions that are historical in nature and explain the thoughts and actions of the people of that era with respect to the Verse of Purification and who it addresses. In view of these traditions, it can be said that this issue—the limitation of the Verse of Purification to the five people of the cloak (ع)—was so well-known among the Muslims that whenever they would see one of them, they would say, “I saw so-and-so, who is of the Ahlul Bayt.” Or they would indicate them and say, “So-and-so is of the ahl al-bayt.” As an example, one can refer to the story of Abu Mijlaz, the details of which have been mentioned in Sunni books of tafsir[5] (Qur`anic commentary).