How do we know that the Qur'an has never been changed?

The belief that the Qur'an has never been changed is supported by several verses within the Qur'an itself and reinforced by scholarly commentary and hadith. One of the key verses that emphasizes the authenticity and unaltered nature of the Qur'an is found in Surah Al-Anfaal, where it states: That is because Allah never changeth the grace He hath bestowed on any people until they first change that which is in their hearts, and (that is) because Allah is Hearer, Knower. 8:53. This verse suggests that divine grace remains intact unless there is a change in the people's hearts, implying the permanence of the Qur'an as a divine gift.

Furthermore, in Surah Yunus, it is stated: And this Qur'an is not such as could ever be invented in despite of Allah; but it is a confirmation of that which was before it and an exposition of that which is decreed for mankind - Therein is no doubt - from the Lord of the Worlds. 10:37. This verse asserts the Qur'an’s unique nature as a divine revelation that cannot be fabricated and confirms its authenticity.

Tafsir Ibn Kathir explains that the challenge posed by Allah to disbelievers in the Qur'an to produce something like it serves as a proof of its unmatched quality and the impossibility of altering its content. The inability of the disbelievers to respond to this challenge is viewed as evidence that the Qur'an’s message has remained unchanged and protected by Allah.

In addition, hadith literature supports this idea. Ibn Abbas is reported to have said, How can you ask the people of the Scriptures about anything while you have Allah's Book (the Qur'an) which is the most recent of the Books revealed by Allah, and you read it in its pure undistorted form? Sahih al-Bukhari 93:613. This highlights the Qur'an's purity and the belief that it has not been distorted unlike previous scriptures.

Thus, both the Qur'an itself and scholarly interpretations affirm the notion that the Qur'an has remained unchanged throughout history, reflecting its divine origin and protection from alteration.