1) Ibn Rushd,(520 h to 595 h) said in his book "Manahijul Adillah Fee 'Aqaadil Millah" page 150:
وهذه هي حال الفرق الحادثة في الشريعة مع الشريعة ، وذلك أن كل فرقة منهم تأولت في الشريعة تأويلاً غير التأويل الذي تأولته الفرقة الأخرى ، وزعمت أنه الذي قصده صاحب الشرع ، حتى تمزق الشرع كل ممزق ، وبعُد جداً عن موضوعه الأول ، ولما علم صاحب الشرع أن مثل هذا يعرض ولا بد في شريعته قال : "ستفترق أمتي على ثنتين وسبعين فرقة كلها في النار إلا واحدة" يعني بالواحدة : التي سلكت ظاهر الشرع ولم تؤوله ، وأنت إذا تأملت ما عرض في هذه الشريعة في هذا الوقت من الفساد العارض فيها من قبل التأويل تبينت أن هذا المثال صحيح ، وأول من غير هذا الدواء الأعظم هم:
الخوارج ، ثم المعتزلة بعدهم ، ثم الأشعرية ، ثم الصوفية ، ثم جاء أبو حامد فطم الوادي على القرى
This was the status of innovated sects with respect to Shari'ah. Each of these sects misunderstood Shari'ah in a way different than the other sects, claiming their understanding to be the objective of the Legislator. This tore the Shari'ah to several pieces, and distanced it from its original position.
The Legislator knew that this was likely to occur so He said: My nation will devide into 73 sects, all will be in the hell fire, except for one". He meant by this "one" the sect which goes by the apparent verses of Shari'ah and does not misunderstand them.
When you look at the amount of deviation that has occurred in the Ummah during this time, you will find that most of it was due to misunderstanding.
And the first to modify this great cure were: al-Khawarij, then Mu'tazilites, then Ash'aris, then Sufis. Then came Abu Hamed who caused the valley to landslide over the villages.
2.Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) said:
"ومَن قال إن الثنتين والسبعين فِرقة كل واحد منهم يكفر كفراً ينقل عن الملة : فقد خالف الكتاب والسنَّة وإجماع الصحابة رضوان الله عليهم أجمعين ، بل وإجماع الأئمة الأربعة وغير الأربعة ؛ فليس فيهم مَن كفَّر كلَّ واحد من الثنتين وسبعين فرقة"
Whoever says that the seventy-two sects have all committed kufr (disbelief) in a way that puts them beyond the pale of Islam has gone against the Qur’an, Sunnah and the consensus of the Sahaabah (may Allah be pleased with them all), and also the consensus of the four imams and others. There is no one among them who regarded each one of the seventy-two sects as disbelievers. [End quote from Majmoo‘ al-Fataawa, 7/218]
4. Shaykh Asim Al Hakeem said
Prophet(salla Allahu alahi wa sallam) told us that the nations before us were split into 70+ sects and his Ummah will be divided into 73.
72 of them are in hell and only one will be admitted into paradise by the grace of Allah(Azza wa Jal). When the companions asked,"O Prophet of Allah, which one would that be?" and he said " the jamaah(the main body of muslims) ." And in another narration he said, " Those who follow that which I and my companions follow."So this is a serious issue. But we have to clarify that when we say 72 sects in hell we don't mean that they are not Muslims. Among the 72 sects they are groups who are Muslims and who will be punished in hell and then permitted into paradise when Allah wills it. Allah would forgive them,providing that He wills it and probably because they were doing the best,they could and they made a mistake by choosing that path .However, among the 72 are sects which are not considered to be muslims such as Qadiyanis,Ahmadis,Bahais etc who will be doomed in hell.
5. Ahmad al-Sirhindi the sufi (d. 1034) said in his Maktubat (Vol. 3, Letter 38):
"It was declared in a Hadith that this Ummah would part into 73 groups, 72 of which would go to Hell. This Hadith informs us that the 72 groups will be tormented in the Fire of Hell. It does not inform us that they will remain in torment eternally. Remaining in the torment of Hell Fire eternally is for those who do not have Iman. That is, it is for disbelievers. The 72 groups, on account of their corrupt beliefs, will go to Hell and will burn as much as the corruptness of their beliefs. One group, the 73rd, will be saved from Hell Fire because their belief is not corrupt. If among the members of this one group there are those who committed evil deeds and if these evil deeds of theirs have not been forgiven through repentance or intercession, it is possible that these, too, will burn in Hell as much as their sins. All of those who are in the 72 groups will go to Hell. But none of them will remain in Hell eternally. Not all of those who are in this one group will go to Hell. Of these only those who have committed evil deeds will go to Hell. The 72 reported groups of bid'ah, which will go to Hell, should not be called disbelievers, because they are Ahl al-Qibla(people of the Qibla in prayer). But, of these, the ones who disbelieve those facts in the Deen that are indispensably required to be believed, as well as those who deny the rules of the Shari'ah which every Muslim has heard and knows, become disbelievers."
6.Al Imaam Muhammad bin Saalih al-'Uthaimeen
"Will The 72 Astray Groups Remain In The Fire?"
Source: Fatwa taken from: ﻟﻘﺎءات اﻟﺒﺎب اﻟﻤﻔﺘﻮح.
Translated by Abu Abdis Siddiq Salaam al-Juyaanee.
As Shaikh Al Allaamah Al Imaam Muhammad bin Saalih al-'Uthaimeen (rahimahullah) was asked, "In the hadeeth, "My Ummah will divide into 73 groups all of them will be in the fire except one."[Hadeeth reported by at-Tirmidhi]
Will they (the 72) groups be in the fire forever or are they from the astray groups from amongst the Muslims?"
The Shaikh (rahimahullah) answered,
"The Prophet (alaihis salaatu wasallam's) statement, My Ummah will divide into 73 groups; all of them will be in the fire except one", does not mean that they all will be in the fire forever. Rather some (of them) commit bid'ah which warrants their staying in the fire, while (others commit) bid'ah which will make the servant deserving of entering the fire but he will not stay therein for eternity. So the situation will all depend on the (type of) bid'ah which is committed and the extent of the differing from that which the Prophet (salallahu alaihi wasallam) and his companions were upon."
It was then asked, "One of them will be in Jannah"; does this mean that a man from Firqatun Naajiyyah (the victorious group) will never enter the fire?"
The Shaikh (rahimahullah) then answered,
"(Either) he would not enter the fire or, he would enter the fire but not remain therein forever." It was then asked, "How do we understand this?"
The Shaikh (rahimahullah) said,
"We say for example, people (Muslims) are of four categories (with regards to this issue),
The First: An innovator who commits a bid'ah that is mukaffirah (which takes one outside of Islam). And he has absolutely no Sunnah with him. So this one will remain in the fire, and there is no difficulty in this (i.e. with regards to his ruling).
The Second: An innovator who commits a bid'ah that is mufassiqah (which does not take one outside of Islam). So this one deserves to enter the fire but he will not stay therein forever.
The Third: A pure Sunni (Salafee), this one will enter into Jannah and does not deserve to enter the fire. And if he were to enter it (the fire) due to some other sin, then he would not stay therein forever.
The Fourth: A Sunni (Salafee), who has mixed both good and bad deeds. This one deserves to enter the fire but would not stay therein forever." (end quote)
7. The Permanent Committee for Islaamic Research and Fataawa
Question: What is the meaning of the following hadeeth:
((My ummah will be divided into seventy three sects. All of them will be in the Fire except one?)),
Who is that sect ? And will the seventy two sects live forever in the Fire, as the mushrik will or not? And does the term "ummah" of the Prophet (sal-Allaahu 'alayhe wa sallam) apply to thos who follow him as well as those who do not, or is it to the former only?
Response: What is meant by the term "ummah" in this hadeeth is the ummah of response (ummatul-ijaabah - those who responded to the call to Islaam after having been invited), which shall be divided into seventy three sects; seventy two of which are deviant, who practice innovated religious practices that do not constitute apostacy. Each shall be punished in accordance to the innovations and deviation (it practiced), except for those who Allaah pardons and forgives. Their final abode will be Jannah. The only sect that will be safe is Ahlus-Sunnah wal-Jamaa'ah, who adhere to the Sunnah of the Prophet (sal-Allaahu 'alayhe wa sallam) and hold fast to what he and his companions (radhi-yallaahu 'anhum) were holding to. It is they about whom the Prophet (sal-Allaahu 'alayhe wa sallam) said:
((A group of my ummah shall remain steadfast, on the truth, victorious, unharmed by those who oppose them, and do not support them, until the death or until the Day of Resurrection)), [Saheeh al-Bukhaaree, nos.71 and 3641, and Saheeh Muslim, no.1920]
As for those whose innovation casts them out of Islaam, they belong to the ummah of invitation (ummatud-da'wah - those to whom the Prophet (sal-Allaahu 'alayhe wa sallam) was sent to invite to Islaam), not the ummatul-ijaabah. They shall remain in the Hell Fire forever, and this is the most valid opinion.
It is also said that the term "ummah" in this hadeeth means ummatud-da'wah, which is a general term indicating all those to whom the Prophet (sal-Allaahu 'alayhe wa sallam) was sent (i.e. mankind) those who believe and those who do not believe. Whereas the term "the saved sect" is the ummatul-ijaabah, which strictly applies to those who believe in the Prophet (sal-Allaahu 'alayhe wa sallam), truthfully and die in such a state (of belief). This is the sect that whill be saved from the Fire; either by prior punishment or without prior punishment, and their final abode will beJannah, (inshaa.-Allaah).
As for the seventy two sects (in the second opinion) they are all, excluding the saved sect, disbelievers who will live forever in the Fire. Hence, it is clear that the ummatud-da'wah is more general in connotation than the ummatul-ijaabah. That is to say, whoever belongs to the ummatul-ijaabah belongs to the ummatud-da'wah, while not everyone of the ummatud-da'wah belongs to the ummatul-ijaabah.
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet (sal-Allaahu 'alayhe wa sallam) and his family and his companions.
Fataawa Islaamiyyah - Volume 1, Page 16
8. Shaykh Muhammad al-Hassan Walid Dido al-Shanqiti was asked
Are the sects that are mentioned by the Prophet in the Ḥadīth to remain in the hellfire forever? And is there any way in which it is possible for the Ahl al-Sunna to be united with them?
The statement of the Prophet that, "The Jews splintered into seventy one sects, the Christians splintered into seventy two sects and my Umma will splinter into seventy three sects," this much of the ḥadīth is authentic. It has been transmitted by al-Ḥākim [al-Naysābūrī (d. 405 AH)] and others, and it is authentic in its various narrations. As for the additional phrase (ziyāda), namely, "all of them are in the hellfire except one," or, "all of them are in Heaven except one," or "whoever [follows] what I and my Companions [follow...]," all of these additional phrases are inauthentic. Thus the authentic ḥadīth is only the affirmation [that there will exist] sects, and this is one of the signs of prophethood [of Muḥammad, and one of its proofs. But as for their being "in the hellfire," or "in Heaven," or, [following] what he and his Companions [follow]; none of these [variant narrations] has authentically reached us from the Prophet.
As for the sects within this Umma, they are those which [promote] reprehensible innovations and misguidance within the faith, and whose followers are not disbelievers [in Islam]—for whoever dies testifying that there is no god but God and that Muḥammad is the Messenger of God will not remain in the hellfire forever, even if they were misguided and an innovator, however great their disobedience may be. Rather God will either forgive them, or punish them to the extent that they have disobeyed Him, and then He will take them out of the hellfire. Indeed God will bring forth groups of people on the Day of Resurrection who have become blackened and scorched [in the hellfire] and cast them into the River of Life. [Therein] their bodies shall sprout as a seed of a desert plant sprouts in the dross of a torrent, and then they shall be entered into Heaven.Additionally, they may be punished in their graves—and the punishment of the grave is one of the means of expiating sins [...]—such that when they are brought forth on the Day of Resurrection, they will already have been recompensed for their innovation and sin.
Source of the fatwa of Sh Shanqiti http://www.suhaibwebb.com/islam-studies/faqs-and-fatwas/shaykh-al-dedo-on-the-sects-of-the-umma-translated-by-u-abdullah/