Taḥrīf (Arabic: تحريف, "distortion, alteration") is an Arabic term used by Muslims for the alterations which Islamic tradition claims Jews and Christians have made to the revealed books, specifically those that make up the Tawrat (or Torah), Zabur (possibly Psalms) and Injil (or Gospel). Traditional Muslim scholars, based on Quranic and other traditions, maintain that Jews and Christians have changed the word of God.
Although belief in tahrif of the Qur'an is non-standard, it is better to reserve the word kufr for the things that Allah directly uses it for.
The Qur'an does not directly say that belief in tahrif is kufr. (Rather, some people assert this based on a deduction/interpretation of a verse, not a direct statement.)
The word kufr tends to be thrown around quite casually these days. There is rarely any benefit to accusing people of kufr or labelling Muslims as kafir just because one thinks they are incorrect in their belief. It is quite sad that this intolerance has developed today. The classical Islamic era seems to have been much more tolerant and open to discussing differences of opinion regarding theology. This is not to say that every view was always right, but it is better to be able to discuss things rationally rather than to shut down dissenting views by just labelling and attacking (verbally or sometimes physically).
Some Shi'i scholars have accepted the idea of deletion or rearrangement of material from the Qur'an based on narrations.
Some Sunni narrations also discuss deletions of material in the Qur'an, so it is not a Shi'i-only subject.
Most Shi'i scholars today reject those narrations and reject the idea of tahrif in the Qur'an. You can find a good argument and overview of the narrations and the subject in https://www.al-islam.org/al-bayan-fi-tafsir-al-quran-prolegomena-quran-s...
This can be a very sensitive and taboo subject because it is generally taken as a primary pillar and fundamental belief of Islam that nothing in the Qur'an has ever been changed (apart from the minor variations in qira'at).
Shi'is are also particularly sensitive because they feel defensive because they feel they have to "prove" to Sunnis that they have the same Qur'an. (And, in fact, Shi'is do use the same Qur'an and same recitations as Sunnis.)
However perhaps it's good to step down from the ideologically and sectarianly charged nature of this discussion and just take it as it is. If some people held this view, it was their view, and that is that.
There are some hadith along those lines. It has been suggested that these are forged hadith. In some cases, when the ayah is presented differently, with insertions, it has been suggested that this may have been an explanation or gloss by the speaker which was later misunderstood as a quotation of the entire ayah.
It is true that there are a few hadith along these lines both in Sunni and Shi'i texts.
Quran is intact with out any distortion whatsoever. There are narrations in Sunni books like Bukhari, Muslim, Al-Tirmithi, Al-Nasaa'ee, Ibn Maajah, Muwatta' Malik, Musnad Ibn Hanbal and other well known books claiming stories about distortion in some Suras of Quran. Our authentic evidence that Quran is intact, made our leading Ulama reject any narration contradicts with the fact that Quran is intact even if it the narration is mentioned in a Shia book. Such narrations in Shia books are much less than in Sunni books and some of them were copied from Sunni books. Such narrations are either fabricated or misunderstood.
Bukhari in Hadeeth number 4608 narrated from Umar ibn al-Khattab different words in Quran which never recited by the Prophet Muhammad (SAWA). Bukhari narrated in Hadeeth number 6327 and 6328 from Umar ibn al-Khattab a claimed verse on stoning the old man and old woman. Such verse is not in Quran but Umar said it is. These are just few examples of long list of such rejected Sunni narrations on this matter.
'The fact which we believe in according to most authentic evidence from Ahlul Bayt (AS) is: Quran is intact and preserved and protected by Allah (SWT) from distortion.
Anyway it is just a single hadith whereas the Quran has been transmitted in a lot of ways, so it is probably just an erroneous hadith and doesn't pose a serious challenge to the authenticity of the Qur'an.
Besides, if someone was going to intentionally lose a part of the Qur'an, one would think it would be about a more controversial subject than how many times a baby should be suckled to be mahram. And it is unlikely that it would be lost accidentally.
Shia believe that Quranic text is intact and no one can change it as Allah (SWT) promised in Quran (We Have revealed the Thikr (Quran) and We Are keeping it intact) Sura 15, Verse 9.
Uthman removed he Tafseer which was mentioned by the Prophet Muhammad (SAWA) on some verses and written by Imam Ali (AS). The Quranic text remains the same.
Our Shia faith in Quran is: Quran is absolutely intact and saved by Allah The Glorious from any change, distortion or alteration. Narrations which suggest change or distortion in Quran are mainly in Sunni books including narrations from Umar Ibn Al-Khattab who claimed that Sura Al-Ahzab used to be as long as Sura al-Baqara. (al-Soyooto, Al-Dorr al-Manthour 3:208) and Ayisha who claimed that a Sura was eaten by a pet (Sunan Ibn Maajah 1:625).
Few narrations in this regard came from Sunni books to some of our Shia books but our leading scholars were and are always very clear in rejecting any claim against the fact that Quran is intact. Some narrations in our books might mean that people distorted the meaning (Tafseer) of some verses away from the real meaning explained by the Prophet (SAWA) and his Ahlul Bayt (AS) which is a sad fact, but it never means that Quranic text was distorted by any way.
Leading Shia scholars al-Shaikh Al-Saqouq (381 H), al- Shaikh al-Mofeed (413 H), al-Sayyed al-Mortadha (436H), al-Shaikh al-Toosi (460 H), al-Shaikh al-Tabrasi (548H), al-Shaikh al-Bahaa'ee, al-Faydh al-Kashaani, al-Shaikh Kashif al-Ghitaa', al-Sayyed Sharaf al-Deen, Allamah Tabataba'ee, al-Sayyed al-Kho'ee, al-Sayed al-Khomaini, al-Sayyed al-Gulpaygani, al-Sayyed al-Borojordi, al-Shaykh al-Saafi, al-Sayyed al-Sistani, al-Sayyed al-Hakeem and all our leading scholars are very clear in confirming the fact that Quran is absolutely intact from any change or distortion.
It is the consensus of the Shi'a scholars that there is no distortion in the Qur'an. You can read more about this topic in the article below that gives references to the statements of a variety of scholars.
A famous scholar Ayatullah Sayyid Abu'l Qasim al-Khu'i has a detailed discussion around this topic in his book that you can also go through for a more in-depth treatment of this subject.
Not at all.
All prominent Shia Scholars believe that Quran is intact and never been distorted.
Shia enemies put false allegations on us including in this matter. If they read our books properly, they will see that our faith is that Quran is intact. Sunni books have narrations from Omar that Sura al-Ahzaab was like Sura Baqarah, and from Ayisha that a Quranic chapter was eaten by a pet. These Sunni narrations and any similar narration are rejected by us because we believe that Allah (SWT) has promised to save and protect Quran from any discretion. (Sura Al-Hijr, verse 9).
We do believe that many persons tried and still trying to twist the meaning of some Quranic verses to make it in accordance to their wrong claims, but Qurani'c words are intact.
Shia scholars have written books on this subject confirming our faith in the intact Quran.
Quran is complete, intact and unchanged. This is the faith of leading Shia scholars including Ayatullah Sistani, Ayatulla Al-Khoei, Shaikh Al-Sadouq, Shaikh Al-Toosi, Sayyed Al-Murtadha, Shaikh Al-Mufeed, Shaikh Al-Tabrasi, Shaikh Kaashif Al-Ghitaa' and thousand of Shia scholars.
There are some Sunni narrations from Umar and Ayisha that Qur'an which is available in our hands is not complete (Saheeh Muslim 1050, Musnad Ahmad 5:132, Al-Mustadrak 4:359, Al-Kashshaaf 3:518 etc), with few weak narrations in few Shia books, but there is no values for such narrations. Our authentic evidence from Ahlul Bayt (AS) is unchallengeable that Qur'an is complete and intact.
The authentic Hadeeths from the Holy Prophet (SAWA) and his holy
progeny, the Ahlul Bayt (AS) are confirmed through a very strict
procedure of checking every narrator and every narration which means
that the scholars check every narrator whether he is trustworthy or
not and up to what extent he is trustworthy according what has been mentioned about him in the books of Rijaal. If all the narrators are
trustworthy then the Hadeeth will be taken as authentic. We also study
the content and the text of the Hadeeth which should not contradict
any Qur’anic verse or any other authentic Hadeeth. By this very strict
procedure our scholars are sure that no unauthentic Hadeeth can be
taken as authentic. Now the question of whether all the authentic
Hadeeth are available or not, the answer is that all the authentic
Hadeeths are with infallible Ahlul Bayt (AS). The Imam (AS) of every
time is the authority and he has all the knowledge about every Hadeeth
from the Holy Prophet (SAWA) and the Ahlul Bayt (AS). We cannot say
now that our knowledge or all our scholars’ knowledge today has all
the Hadeeths but for sure, our Imam, Imam al-Mahdi (ATFS) has all that
knowledge and he is guarding and supervising and supporting the
followers of Ahlul Bay (AS) and guiding the scholars to the real
knowledge of Islam.
Thank you for your question. There certainly was corruption of the hadith from the Prophet (saw) and Imams (as) even during their lifetimes and so at times the companions of the Imams (as) would check hadith that they did not recognise with the Imams themselves. Since the time of the ghayba one of the most important concerns of scholarship is to deal with the corpus of hadith and define benchmarks for deciphering authentic traditions from less authentic ones. There are a number of methodologies for doing that, some of which are quite technical but are discussed in the sciences of usul, hadith and rijal.
May you always be successful