Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
A Muslim should not occupy himself with things that are spread by Allah's enemies, such as doubts and lies about Qur'an, knowing that Allah the Almighty guarantees to guard this last Revelation from change; Allah Says (interpretation of meaning): {Verily We: It is We Who have sent down the Dhikr (i.e. the Qur'ân) and surely, We will guard it (from corruption).} [15: 9].
He The Almighty obligated and authorized the scholars of Ahl-al-Kitab (Jews and Christians) to guard the past Revealed Books, because their missions were limited to their special place and time; therefore they (the Books) were not eternal nor universal. Allah Says (interpretation of meaning): {Verily, We did send down the Taurât (Torah) [to Mûsa (Moses)], therein was guidance and light, by which the Prophets, who submitted themselves to Allâh's Will, judged the Jews. And the rabbis and the priests [too judged the Jews by the Taurât (Torah) after those Prophets] for to them was entrusted the protection of Allâh's Book, and they were witnesses thereto. …} [5: 44].
But regarding the Qur'an it is meant for eternity and for all creation (men and jinn), because it is Allah's last word to all. So you will not find any historical documents or ancient books that are protected, kept and honored as much as the Qur'an. And from its aspects we find that:
- Qur'anic recitation and the methods of its performance are guarded just like the Prophet (Sallallahu Alaihi wa Sallam) and his companions were performing it, with all "Makhareg" (letter exits), attributes, "Madd" (distending the letter), "Qasr" (shortening the letter). All that has been memorized and written down and the hands of the mischievous cannot harm it.
So whoever contemplates the Qur'an fairly, will realize the unquestionable fact that this Book is Allah's Word and it is preserved by Him bearing the miraculous signs regarding its text and its significance. These signs we can find also in the words, purity of the language and the good style, the Qur'an bears concepts, tenets, ethics, decencies, worshiping, laws, rules, stories, news, lessons and examples.
So, we advise our questioner not to occupy himself with fraudulent claims of enemies unsupported by any facts, knowledge or rational evidence.
Allah knows best.