In response to the first section of the question, the ayah of taṭhīr is located in the middle of another larger ayah, but the most this issue can imply is that it is out of context when considering the preceding and following section of the ayah and in the case of not being exclusive we can only deduce that it is more general and therefore includes the wives of the Prophet (S.A.) as well. However, we must note that first of all, supposing this to be the case, this will create an apparent meaning (ẓuhūr) for the ayah, but the apparent meaning cannot be accepted as the precise interpretation when we have many indications pointing at a different interpretation. Secondly, this is on top of the fact that the order and flow of the verse (siyaq al-ayah) itself doesn’t suggest that the ayah consists of the wives of the Prophet (S.A.) either.
As regards to the first note: Despite the fact that an aversive (mu’tariḍah) sentence disrupts the form and order of the verse, it actually adds eloquence to the sentence when indications of the true meaning accompany it. Therefore, there is no necessity in saying that just because the verse is located amongst other verses speaking about the wives of the prophet, that it covers them as well, because the intention of this part of the verse may be to the attention of the readers, or just a parenthetical phrase pointing to certain individuals, namely, “The Companions of the Cloak”, exclusively. A lot of evidence backs this claim, for example:
1. According to a set of traditions, the ayah of taṭhīr has been revealed separately and the Prophet (S.A.) deliberately demanded to place this ayah in the middle of the larger ayah so that no one would fall under the impression that the Ahl al-Bayt (S.A.) might prefer this lowly world over the Prophet (S.A.), as was the case for the wives of the Prophet (S.A.).
2. The tone of God’s word changes and after using several plural feminine pronouns (کنّ) that refer to the wives of the Prophet (S.A.) He uses the plural masculine pronoun (کم).
3. According to terminologists the term Ahl (household) does not denote wives unless a metaphoric usage (majāz) is intended, which is why, Umm Salamah requested the Prophet (S.A.) to allow her to also be a member of the Ahl al-Bayt. As evidence to this claim, Zayd ibn Arqam says: “The title Ahl al-Bayt cannot be used to denote wives.”
4. Not a single wife of the Prophet has claimed to be part of this phrase, even though ‘Aishah was in dire need of such a justification in the ‘Battle of the Camel’.
5. The word “تردن” (referring to the will and choice of the wives of the prophet) in verse 29 of Surah Ahzāb suggests that God does not have an extraordinary plan of life formulated for the wives of the Prophet (S.A.), while the Ahl al-Bayt have been destined to be cleansed from abomination.
6. “ال” in the word “اهل البیت (Ahl al-Bayt)”, is pointing to something that actually took place before, meaning the event of “The Cloak”. Therefore Ahl al-Bayt (A.S.) is a demonstrative title (unwān-imushīr) like Āl-i‘Abā, AṣḥābKisā’ and Yawm al-Dār.
As to the second point: The Prophet (S.A.) is being told in these verses to address his wives in this manner and remind them: “یا ایها النبی قل لازواجک...”.
Subsequently, God addresses the household of the Prophet (S.A.) and the Prophet (S.A.) himself to imply that all of these demands and prohibitions pertaining to the wives of the Prophet (S.A.) are meant to prove that the Ahl al-Bayt are pure in all aspects, even in respect to those related to them, because Allah Almighty has wished to remove all abomination from the Ahl al-Bayt. The form and order of the ayah is thus, compatible with the fact that the ayah of taṭhīr is confined to the Companions of the Cloak.
Now, to attend to the second section of the question we must say that in light of the preceding explanation there might not be any need for a separate answer, but to emphasize on this point, it has been narrated many times through mutawātir (successively narrated) that the Ahl al-Bayt of the Prophet (S.A.) are: Imam Ali, Lady Fatima, Imam Hassan and Imam Hussein (A.S.) and the remaining A’imah fall under the category described in the ayah by ta’wīl (symbolical exegesis) due to having the same essential elements.
What has been referred to in the question is exactly what others have said, claiming that since the ayah has been mentioned within the context of ayahs pertaining to the wives of the Prophet (S.A.), it must, at least, be describing them as well, but this isn’t an acceptable claim and one that can be proven, because there is much evidence is against it.
Considering these points will definitely help us in understanding the truth:
1. Despite the fact that the ayahs of the Quran have been put in order by the Prophet (S.A.), in addition to being revealed down onto him, there is a group of traditions stating that the ayah of tathīr has been revealed apart and separate from the neighboring phrases of the ayah, while not a single hadith has stated that this ayah was revealed along with the ayahs of the Prophet’s wives together. As evidence, if this phrase (ayah of taṭhīr) is cut out of this ayah it won’t affect the coherence and order.
If it has been squeezed into this section of the Quran and meant to explain how the family of the Prophet as a whole was divided into two groups, one group being the prophet’s (S.A.) wives and the other, the Ahl al-Bayt of the prophet; it was meant to remind us that all of the prophet’s family members and relatives were not the same; that some of them were specifically blessed amongst others by being
cleansed of abomination.
In other words, even if we concede that the beginning and the end of the ayah are about the prophet’s (S.A.) wives, two distinct factors suggest that the term Ahl al-bayt refers to Imam Ali, Lady Fatima, Imam Hassan and Imam Hussein (A.S.):
A. Iltifāt (Conversion):Iltifāt is a literary technique, which beautifies the statement similar to what we see in surah Fātiḥat al-Kitāb where the ayahs go from addressing the absent (الحمد لله) to the present (ایاک نعبد). This technique has been used in the ayah of taṭhīr to indicate how important it is to exonerate the Ahl al-Bayt from obscenity by demanding the wives of the Prophet (S.A.) to be aware of their actions so that no deficiencies could be linked to the Ahl al-Bayt, due to their relations.
B. I‘itirāḍ (parenthetical): M‘utariḍah (parenthetical) sentences are seen largely in the words of eloquent writers. A mu‘tariḍah sentence is a sentence placed in-between two other sentences in order to emphasize the significance of a certain subject and allow it to grasp more attention than usual. This method has been implemented in the Quran many times. In this ayah, the technique of i‘itirāḍ has been used so that no one perceives that the Ahl al-Bayt are equal in status to the wives of the Prophet (S.A.). This is because in the case where the Quran is talking about how the wives of the Prophet must refrain from doing abominable actions, one might wrongly perceive that the Ahl al-Bayt are as vulnerable to sin as they are, when the matter of fact is that they are innocent of such practices, hence, the mu‘tariḍah sentence: “انما يريد الله ليذهب...”.
2. After using the female plural pronoun twenty consecutive times, we see a clear shift of articulation and variation of tone in God’s words by addressing his addressee with a male pronoun. This is definitely the most convincing indication for us to let go of the apparent meaning and accept the interpretation, which doesn’t include the wives of the Prophet.
3. Experts assert that the term “Ahl” does not denote wives, except metaphorically, which is why in ayah 73 of surah Hūd the word Ahl al-Bayt has been used for one’s spouse, but not every usage of a word for a certain meaning shows that it is the literal meaning of the word; it can also be used in its metaphoric meaning, of course with the appropriate context clues to determine that metaphoric meaning. However, in the ayah of taṭhīr there are indications that this meaning isn’t intended, let alone the indications that establish that interpretation. It is due to this same fact (that the literal meaning of the term didn’t cover the wives of the prophet) that Umm Salamah asks the Prophet (S.A.) whether she is part of the Ahl al-Bayt or not, and whether she can be part of them or not. If the meaning of the term “Ahl” was to cover the wives of the prophet literally, it would leave no room for Umm Salamah’s question.
Accordingly, Zayd ibn Arqam states: “The title Ahl al-Bayt doesn’t include the wives.”
4. Based on Sunni traditions, ‘Āyishah and Umm Salamah have both clearly acknowledged that the ayah of taṭhīr didn’t apply to them. According to ‘Allāmah A’mīnī, Āyishah would have definitely posed this ayah as justification in the Battle of the Camel, but she didn’t, even though such a justification was extremely needed.
Despite the evidence and above arguments there are two groups that claim the ayah of taṭhīr was revealed in description of the wives of the Prophet (S.A.). The first group are, Akramah, Muqātil ibn Sulaymān and ‘Urwat bin Zubayr who have been accused of propagating their personal opinion and lying about the hadith attributed to Ibn Abbās.
The second group includes a few Sunni interpreters of the Quran who perceive the harmony and contextual uniformity of the ayah to be the reason. However, as proven and discussed previously, this cannot be accepted due to all of the other evidence and indications within the ayah.
5. The word “تردن” in ayah 29 of surah Aḥzāb demonstrates that God Almighty does not have an extraordinary plan formulated for the wives of the prophet (S.A.), rather he has left them to their free-will; if they decide to truly honor the rank of being the Prophet’s wife, they can do so, and if not, it is their decision and they are doomed to face the consequences.
But in the actual ayah of taṭhī, “انما يريد اللَّه” suggests that God’s pre-eternal providence and Takwini will has been set upon creating a family that is clean of all abomination.
To explain, there are many indications in the ayah of taṭhīr that simply confine the cleansing of abomination to the Ahl al-Bayt. For instance, the term “انما” or how “عنكم” has been brought before “اهل البیت” and how “اهل” is maftūḥ are all signs of exclusivity.
Therefore, the Ahl al-Bayt have been chosen to be granted with special virtues that none other have, and the verb “یرید” demonstrates this gesture of how God has decided willfully to separate them apart and cleanse them from abomination. This isn’t a common blessing granted to everybody, but rather to those who guide themselves beneath the rain of blessings of God,as a result of preparing the grounds for it.
This divine providence will never fail and cannot pertain to the wives of the Prophet because in the former ayahs we see that God has addressed them, warning them of the possibility of going astray by desiring worldly possessions and thus losing the honor of living up to moral expectations of being the wives of the Prophet.
6. “ال” in Ahl al-Bayt is making reference to an incident that has already taken place, meaning that in this verse, the term “Ahl al-Bayt” is a referential term (‘unwān mushīr), a term which points to a certain event in the past, similar to how Yawm al-Dār refers to a specific event when the Prophet (S.A.) gathered everyone in the house of Abū Tālib to announce his prophecy. It actually denotes a certain group of people who were gathered beneath the cloak of the Prophet (S.A.) in the house of, according to traditions, Umm Salamah, namely, the Prophet himself, Ali, Fatima, Hassan and Hussein (A.S.); this means that the term Ahl al-Bayt is no different than the terms of Āl ‘Aba and Aṣḥāb Kisā’ in who they make reference to.
Technically speaking, this is an external (khārijīyyah) proposition not a reality (ḥaqīqīyyah) proposition and the subject of an external proposition is usually what is outside and exists externally. For instance, if one says: respect these two scholars, they mean for the two scholars who exist externally and outside to be respected, and it is obvious that the description is confined to the subject. Now, the evidence backing the fact that this is an external proposition:
A. In the previous and following ayahs"بيت" in its plural form has been combined with women in construct phrases, referring to the rooms of the wives, so "البيت", which is preceded by the definite article ال must be pointing to a specific room.
B. According to traditions, the Prophet was definitely one of the Ahl al-Bayt. With this in mind, could there possibly be another plausible interpretation of the ayah that would include the prophet in the Ahl al-Bayt?
C. In ayah 73 of surah Hūd the term Ahl al-Bayt has been mentioned with an “ال” which in that context refers to the household living in Prophet Ibrahim’s house, meaning Prophet Ibrahim and his wife Sareh. The possibility of it including the wives of Ibrahim (S.A.) or his relatives is insignificant and this should help us in interpreting the same term in the ayah of taṭhīr.
7. These verses and the verse of taṭhīr lead us to the conclusion that the wives of the Prophet (S.A.) aren’t even partially addressed by the ayah let alone being the only addressee of the ayah and that the Companions of the Cloak are the real addressee.
In these verses, the Prophet is addressed: “يا ايها النبى قل لازواجك...”; meaning that God has demanded the Prophet to leave his wives in free will to choose between this world, it’s material possessions and the Prophet and God Almighty. He additionally adds: “يا نساء النبى من يأت منكنّ بفاحشة مبينة يضاعف لها العذاب و...” and this is addressed to the Prophet’s wives or in continuance of his demands to the Prophet to convey to his wives or as an example of iltifat (turning or converting your attention to someone) where God directly turns towards the wives of the Prophet and addresses them directly.
The reason for conversion (iltifat) in this ayah is that the wives of the Prophet (S.A.) are linked to the Prophet, so for the sake of the Prophet’s position and status He addresses them directly and states that if one of them commits a bad deed in public she will be punished twice as usual. Afterwards He addresses the Prophet and his household in order to point out the reason as to why he made all of these demands and prohibitions, which is to renounce this household of all abomination.
Therefore, “انما يريد الله ليذهب عنكم الرجس...” means that God has legislated that the wives of the Prophet must obey his demands to distant the Ahl al-Bayt and the Prophet’s position from abomination since He says: “ليذهب عنكم الرجس” instead of “لإذهاب عنكم الرجس”; the beginning letter (ل) is for showing the philosophy as to why He made these demands. So the verse is saying that God has certain demands from the wives of the prophet, and the reason he has these demands is to keep the Ahl al-Bayt away from any form of abomination being associated with them.
This proves that God Almighty has undoubtedly decided to cleanse the Ahl al-Bayt from abomination. This is a fundamental principle, a very essential and important one. It is so important that God doesn’t give consent to the wives of the Prophet (S.A.) who aren’t members of the Ahl al-Bayt but rather are simply their relativesto do something wrong, due to their connection with the Ahl al-Bayt through being wives of the prophet. Thus, by legislation, He demands that those of them who commit good will be rewarded twice and those committed bad will punished twice as bad as well. To conclude:
1. Confining the ayah of taṭhīr to the people of the mantle isn’t incoherent to the context of the ayah and if it isn’t the first thing that might come to mind when reading the ayah and seeing the context, we must say that when we slightly ponder upon the indications and the fact of the usage of an aversive sentence we are compelled to believe it to be restricted to that group.
Before ending we must answer this question, how have the rest of the nine imams after Imam Husayn (AS) been included as part of the Ahl al-Bayt?
In response, according to this interpretation of the ayah that the household of the Prophet are being referred to in this ayah, the limit and boundary as to where it ends among the Prophet’s household is definitely understood by the indications accompanying it, which imply that the ayah is trying to put them forward and separate them as leaders among the Muslims.
A. When standing among the Muhājirīn and Anṣār, Imam Ali argues for his priority at being the leader by reminding that he is one of the Ahl al-Bayt.
B. Imam Ali (A.S.) proves his worthiness for leadership by referring to the ayah of taṭhīr.
C. When Imam Hassan is chosen as the caliphate of the Muslims he reads the ayah of tatḥīr as his reason for eligibility of being the caliph.
D. Imam Hussein has done the same as well.
E. Every morning when the Prophet (S.A.) would go the mosque for morning prayer, he would stand before Lady Fatima’s door and read this ayah: “انما يريد الله ليذهب...”.
Could the prophet mean anything else other than to tell the people not to follow anyone else after him except his household?
Therefore, this is why the term includes the rest of the imams as well, for they are the true leaders of this Islamic ummah.
This is also true even if we believe the term to be a referential term and the “ال” in Ahl al-Bayt to be that of external reference to what exists there and then, because even according to this standpoint, the term Ahl al-Bayt is looked at from two perspectives:
1. It is looked at from the perspective of its revelation.
2. It is looked at considering the ruling that has been allocated to it, meaning the cleansing of abomination.
Regarding the first usage the word Ahl al-Bayt would merely apply to the five Companions of the Cloak, the same five who were under the cloak in that certain day and event.
But according to the second type of usage the rest of the imams (A.S.) are equal to the Companions of the Cloak and this fact applies to them as well. This might be the reason why the Prophet (S.A.) said: Salman is a member of us, the Ahl al-Bayt.
In response to Ibn Kathīr, Imam Sadiq (A.S.) says: “The Ahl al-Bayt are those five people but the rest of the imams are considered to be referred to in this ayah in light of this ayah “اولوا الارحام بعضهم اولى ببعض فى كتاب الله”; meaning that the interpretation of the ayah includes all of the imams. The verse that interprets the ayah of taṭhīr is the ayah of u’lu al-arḥām, which proves that the verse of taṭhīr applies to the other imams (A.S.) as well, of course indirectly and not through its apparent meaning.
Tabatabai, Al-Mizan, vol. 16, pp. 311-312.
 Karaki, Nafahaat al-Lahut, p. 85; Mudhaffar, Muhammad Hasan, Dala’il al-Sidq; Sayyid Ja’far Murtadha Amili, Ahle Bayt dar Ayeye Tathir, pp. 58-61.
 Yusuf:28 and 29; Naml:34 and 35; Baqarah:73-75; Waqi’ah:76; Luqman:13 and 16.
 See: Ahle Bayt dar Ayeye Tathir, pp. 60-62; Ishraqi, Shahab al-Din and Fazil Lankarani, Ahle Bayt, pp. 53-81.
 Semantics have put a difference between “Ahl Bayt” and “Ahl Rajul” and consider using Ahl Bayt for one’s wives to be metaphorical and not literal. See: Taaj al-Arus, vol. 1, p. 217; Lisan al-Arab, vol. 1, p. 38; Mufradat Raghib, p. 29. According to some prophetic narrations, although Umm Salamah was one of the wives of the prophet, yet he never accepted her to be of the “Ahl al-Bayt”. See: Suyuti, Al-Durr al-Manthur, vol. 5, p. 198; Mushkil al-Athar, Tahawi, vol. 1, p. 334; Muhammad ibn Jarir, Tabari, Jami’ al-Bayan, vol. 22, p. 7; Nafahat al-Lahut, p. 84; Mustafa ibn Ismail Dameshqi, Mirqaat al-Wusul, p. 106; Bihar al-Anwar, vol. 35, pp. 217 and 228.
 See: Tafsir Ibn Kathir, vol. 3, pp. 484-485; Bahrani, Sayyid Hashem, Ghayat al-Maram.
 Ibn Taymiyyah, Minhaj al-Sunnah, vol. 4, p. 21; Sahih Muslim, vol. 7, p. 123; Bihar al-Anwar, vol. 35, p. 230 and vol. 23, p. 117; Ibn Hajar Asqalani, Al-Sawa’iq al-Muhriqah, p. 147; Bahrani, Sayyid Hashim, Al-Burhan fi Tafsir al-Quran, vol. 3, p. 324; Bayadhi Amili, Al-Sirat al-Mustaqim, vol. 1, p. 185; Shushtari, Qadi Nurullah, Ihqaq al-Haqq wa Ibtal al-Batil, Mulhaqat Ayatullah Mar’ashi Najafi, vol. 9, p. 323, Ahle Bayt dar Ayeye Tathir, p. 119.
 Badran, Abd al-Qadir, Tahdhib Taarikh Dameshq, vol. 4, p. 908; Majma’ al-Bayan, vol. 8, p. 356; Qanduzi, Yanabi’ al-Mawaddah, p. 249; Ibn Hajar Asqalani, Al-Sawa’iq al-Muhriqah, p. 141 and…Ahle Bayt dar Ayeye Tathir, pp. 20-28; Tabatabai, Al-Mizan, vol. 16, pp 316-324.
 Quoted from the book Ahle Bayt dar Ayeye Tathir, p. 78.
 See: Ahle Bayt dar Ayeye Tathir, p. 22; Ishraqi and Fazel Lankarani, Ahle Bayt, pp 53-55; Musawi, Allamah Sharafuddin, Al-Kalimat al-Gharraa’ fi Tafdil al-Zahraa’; Qamus al-Rijal, Sharhe Haale Urweh, Dalaa’il al-Sidq, vol. 2, p. 95; Shushtari, Qadi Nurullah, Ihqaq al-Haqq wa Ibtal al-Batil, vol. 2, p. 502.
 Takwini will is the will that has to do with the action of the person willing, meaning the will that has to do with brining into existence the willing person’s action; both God and man have this type of will. The difference is that man’s will isn't always carried out and is overruled by God’s will. There is also another will referred to as Tashri’i will, which has to do with others’ actions that they do out of their own free will. This will is actually the orders of God that He has for His servants, which they are free to either abide by or disobey; it is their choice.
 See: Ishraqi and Fazel Lankarani, Ahle Bayt, pp 81-92.
 Meaning a title that points to something in the outside world; in cases like these, the title isn't what matters, it is what the title is pointing to that does.
 Arusi Huwayzi, Abd Ali ibn Jum’ah, Tafsi Nur al-Thaqalain, vol. 4, pp 276-277.
 See: Ishraqi and Fazel Lankarani, Ahle Bayt, pp 112-142.
 See: Ahle Bayt dar Ayeye Tathir, pp 38-51.
 See: Tabatabai, Al-Mizan, vol. 16, p. 312.
 See: Ahle Bayt, p. 112.
 Tafsir Nur al-Thaqalayn, vol. 4, p. 275, the hadith of Ihtijaj, and p. 273 the hadith of Usul Kāfī.
 Ibn Abi al-Hadid, Sharh Nahjul-Balaghah, vol. 6, pp 11-12.
 Bahrani, Sayyid Hashim, Ghayat al-Maraam, p. 265; Ihtijaj of Tabarsi.
 Qamus al-Rijal, vol. 6, p. 20.
 Ibn Tawus, Luhuf, p. 53.
 Tafsir Ibn Kathir, vol. 3, p. 483; Musnad Ahmad, vol. 3, p. 259; Al-Kalimat al-Gharraa’ fi Tafdil al-Zahraa’.
 Qamus al-Rijal, vol. 4, 423.
 Arusi Huwayzi, Abd Ali ibn Jum’ah, Tafsir Nur al-Thaqalayn, the narration of Abd al-Rahman ibn Kathir, vol. 4, p. 273.
 Ishraqi and Fazel Lankarani, Ahle Bayt, p. 112-143 and 53-55.