Fundamental Islamic belief about the Holy Book of Qur'an

The Holy Qur'aan is the uncreated Kalaam (speech ) of Allah Ta’ala (God Almighty).

 The Qur’aan being the uncreated Word of Allah Ta’ala refers to that Speech of Allah which is His Attribute and is referred to as Kalaamun Nasafi. 

The Quraan, which is ghair makhlooq (uncreated) is not composed of sound, and letters. 

One who asserts that the Quraan  is makhlooq (created) is a non-believer.
(kitab-ul-Imaan)

We do not argue about the Qur'an and we bear witness that it is the speech of the Allah, Lord of all the Worlds,  which the Trustworthy spirit ( Archangel Jibra'eel Gabriel) came down with and taught the most honored of all the Messengers, Prophet Muhammad sallallahu alayhi wa sallam.  It is the speech of Allah and no speech of any created being is comparable to it.  We do not say that is was created and we do not go against the Jama'ah (Muslim community) of the Muslims regarding it.  (Aqeedatut-Tahaawiyyah By Imam Tahawi)

Beliefs concerning heavenly books

Allah Ta'ala has sent down many small and large books through the angel Jibra'eel alayhis salaam to the prophets so that they may teach the matters of Deen to their respective communities. Among these books, four are very famous: the Torah which was sent to Musa (Moses)  alayhis salaam, the Zabur which was sent to Daud  (David) alayhis salaam, the Injil which was sent to Isa (Jesus) alayhis salaam, and the Quran which was sent to our Prophet Muhammad sallallahu alayhi wa sallam. The Quran is the last of the books. Now, no new book will be sent from the heavens. The instructions of the Quran will remain valid right until the day of qiyaamah (doomsday).  Misguided people changed a lot of things in the other books. But Allah Ta'ala has promised the protection of the Quran. No one can change it in any way.

The Holy Quran is not only preserve in a speech but it also manner of its its pronunciation (i.e accent) and preserve in written form.   The proof is that great majority of Muslims today from the age of 5 and up  are able to read and recite the Holy Quran.   And millions of children under the age of 14 ,Arab or Non-Arab like, have memorized the entire Holy Qur'an.