Taḥrīf (Arabic: تحريف, transl. 'distortion') is an Arabic-language term used by Sunni and Shia Muslims to refer to believed alterations made to the previous revelations of God—specifically those that make up the Tawrat (or Torah), the Zabur (or Psalms) and the Injil (or Gospel). It is also used to refer to what Muslims consider to be the corrupted Jewish and Christian interpretations of the previous revelations of God, known as “Tahrif al-Mana”. This concept holds that the previous revelations of God have been misinterpreted.
The origins of Tahrif are debated. Muqatil ibn Sulayman (8th century) claimed in his tafsir on Quran 2:79 that the Jews had distorted the Tawrat (or Torah), and removed the mention of Muhammad in the Quran  although some academics have doubted this as a true mention of tahrif  al-Kasim b. Ibrahim (9th century), made the claim that the Jews and Christians. had misinterpreted the interpretations of The Tawrat (or Torah), the Zabur (or Psalms) and the Injil (or Gospel). this concept is referred to as "Tahrif al-mana". According to Camilla Adang. The early quranic exegete Al-Tabari believed that there was a Torah that there was a genuine Tawrat (or Torah), by Moses that had been lost and then restored by Ezra alongside a different Torah created by the Rabbis and ignorant Jews. Al-Tabari suspected that the Jews of his time were using this different Tawrat instead of the original Torah by Moses which is why Al-Tabari made the distinction of referring to the Torah of his time as "The Torah that they possess today" Al-Tabari says elsewhere in his Tafsir of Quran 2:42 that the Jews had introduced falsehood with their own hands in the Tawrat (or Torah),  
It is worthy to note that some companions such as Uthman ibn Affan  and most notably Ibn Abbas made some statements that imply he believed the scriptures of ‘the people of the book’ were distorted. In Sahih Bukhari he is quoted saying as narrated by Ubaidullah:
Ibn `Abbas said, "Why do you ask the people of the scripture about anything while your Book (Qur'an) which has been revealed to Allah's Messenger (ﷺ) is newer and the latest? You read it pure, undistorted and unchanged, and Allah has told you that the people of the scripture (Jews and Christians) changed their scripture and distorted it, and wrote the scripture with their own hands and said, 'It is from Allah,' to sell it for a little gain. Does not the knowledge which has come to you prevent you from asking them about anything? No, by Allah, we have never seen any man from them asking you regarding what has been revealed to you!
The corruption of the Biblical text was elaborated more extensively by Ibn Hazm (11th century), who popularized the concept of "Tahrif al-nass," or corruption of the text. Ibn Hazm rejected claims of Mosaic authorship and posited that Ezra was the author of the Torah.
He systematically organised the arguments against the authenticity of the Biblical text in the first (Tanakh) and second part (New Testament) of his book: Chronological and geographical inaccuracies and contradictions; theological impossibilities (anthropomorphic expressions, stories of fornication and whoredom, and the attributing of sins to prophets), as well as lack of reliable transmission (tawatur) of the text.
He explains how the falsification of the Torah could have taken place while there existed only one copy of the Torah kept by the Aaronic priesthood of the Temple in Jerusalem. Ibn Hazm's arguments had a major impact upon Muslim literature and scholars, and the themes that he raised with regard to tahrif and other polemical ideas were modified slightly by some later authors. The Shia Scholar Ibn Babawayh narrated a debate between Ali al-Rida and the Catholicos where Ali al-Rida claimed that the Four Gospels were created and changed after the original Injil (or Gospel). became lost.  
- To deliberately interpret something in a manner that is opposite to the author's intention. To distort the pronunciation of a word to such an extent that the word changes completely.
- To add to or delete a sentence or discourse in a manner that distorts the original meaning. For example, according to Muslim tradition, the Jews altered the incident of the migration of Abraham in a manner that no one could prove that Abraham had any relationship with the Kaaba.
- To translate a word that has two meanings in the meaning that is against the context. For example, the Aramaic word used for Jesus that is equivalent to the Arabic: ابن ibn was translated as "son" whereas it also meant "servant" and "slave".
- To raise questions about something that is absolutely clear in order to create uncertainty about it, or to change it completely.
- Biblical inerrancy
- Categories of New Testament manuscripts
- Criticism of the Quran
- Great and abominable church - Mormon equivalent doctrine
- Islamic holy books
- Internal consistency of the Bible
- Textual variants in the New Testament
- Muqatil ibn Sulayman Tafsir 2:79
- Early Muslim Accusations of Tahrif: Muqātil ibn Sulaymān's commentary on key qur'anic verses by Gordon D Nickel
- Lazarus-Yafeh, Haza (2000). Tahrif. Leiden: Brill. p. 111. ISBN 9004112111.
- Camilla Adang. Muslim Writers on Judaism and the Hebrew Bible: From Ibn Rabban to Ibn Hazm. BRILL, 1996. ISBN 978-9-004-10034-3. page 231.
- Tafsir al-Tabari 2:42
- Tafsir Ibn Kathir 2:79
- The Encyclopedia of Islam, BRILL
- Power in the Portrayal: Representations of Jews and Muslims in Eleventh- and Twelfth-Century, chapter "An Andalusi-Muslim Literary Typology of Jewish Heresy and Sedition", pp. 56 and further, Tahrif: p. 58, ISBN 0-691-00187-1
- Under Crescent and Cross: The Jews in the Middle Ages, p. 146, ISBN 0-691-01082-X
- Ibn Babawayh al-Tawhid, p. 417-441
- Ibn Babawayh Uyun akhbar al-Ridha
- Amin Ahsan Islahi, Tadabbur-i-Qur'an, 2nd ed., vol. 1, (Lahore: Faran Foundation, 1986), p. 252
- Hossein Modarressi, Studia Islamica, No. 77.,Early Debates on the Integrity of the Quran,1993,Page 13
- Al-Itqan fi Ulum al-Qur’an,Jalaluddin Suyuti,Muneer Fareed