"Regarding your question, how can the Quran be the word of Allah if God didn't enter into the world, every Muslim would tell you that the Quran was revealed through Gabriel, no verse was revealed in a direct fashion." - 1moremuslim (see here)
There are many reasons to reject the idea that the Qur’an is or even could be a revelation from God. The following will demonstrate at least one of those ways. Rather than show that the Qur’an is false when judged on the basis of external criteria that Muslims would, on the basis of the Qur’an, object to, such as the Bible, it will be shown that that the Qur’an cannot be a revelation from God on the basis of its own criteria. Simply put: If what the Qur’an says about Allah is true, then what the Qur’an says about itself cannot be true.
According to mainstream Sunni Islam, the absoluteness and utter transcendence of the Allah of the Qur’an preclude the very possibility that he could enter into his (alleged) creation. Indeed, this is a foundational reason why Muslims object to the incarnation, the doctrine that the second person of the Trinity entered into the world, was born of a woman and walked among us.
The idea that Allah cannot enter into his creation is believed to follow from a certain understanding of Allah’s transcendence, which, among other places, finds expression in the Aqida of Imam Abu Jafar al-Tahawi (239-321):
“38. He is beyond having limits placed on Him, or being restricted, or having parts or limbs. Nor is He contained by the six directions as all created things are.”
“51. He encompasses all things and that which is above it, and what He has created is incapable of encompassing Him.” (online source)
Christians also believe that nothing can contain God, but for them this does not mean that God is unable to enter into history, as He not only says that He is the high and lofty one who inhabits eternity, the one whom heaven and even the highest heavens cannot contain, but He also says that He fills heaven and earth, without being limited by them, that He encamps around and dwells in the midst of His people, without being confined to any place, and even says that He is with those who are lowly and of a contrite heart. Moreover, God is also able to reveal Himself in a particular place at a particular time, such as the tabernacle, the temple, and the burning bush, without any of this negating or impinging upon His transcendence. But this is not how Muslims understand Allah’s transcendence. As Ibn Al-Arabi Al-Maliki said in his commentary on the hadith of descent found in Tirmidhi:
What we must believe is that Allah existed and nothing existed with Him; that He created all creation, including the Throne, without becoming indicatable through them, nor did a direction arise for Him because of them; that He does not become immanent, that He does not change, and that He does not move from one state to another. (Aridat al-ahwadhi 2:234-237, as cited in Shaykh Muhammad Hisham Kabbani, Encyclopedia of Islamic Doctrine, Beliefs, Vol 1, As-Sunnah Foundation of America, p. 155-156) (Emphasis mine)
The problems with the Muslim view are manifold. Two of them will be mentioned here.
First, if Allah cannot enter into creation, then he also cannot communicate directly with man. But this contradicts what is said many times over in the Qur’an, not the least of which can be seen in the story of Moses. Although this is not the main way the Qur’an says Allah’s revelation came to man, it is at least one of the ways he is said to have done so.
Also mention in the Book (the story of) Moses: For he was specially chosen, and he was a messenger and a prophet. And We called him from the right side of Mount (Sinai), and made Him draw near to Us, for mystic (converse). (Surah 19:51-52) (Emphasis mine)In spite of the above, mainstream Muslims maintain that those who say Allah appeared to Moses in the fire, that he spoke from the fire, that his words were heard coming from a certain direction, etc., are misinterpreting these verses. Granting this claim for the sake of argument, this leads us to a second and worse problem for the Muslim view. The main way it is alleged that Allah revealed his words to the prophets, particularly to Muhammad, is through the medium of the angel Gabriel. Supposedly this gets Muslims off the hook by suggesting that it is Gabriel rather than Allah who speaks to man. But given the claim that Allah cannot enter into creation, not only would it have been impossible for Allah to communicate directly with Moses, or anyone else before or after him; it would also be impossible for Allah to communicate with man indirectly, even through an angelic medium.
Has the story of Moses reached thee? Behold, he saw a fire: so he said to his family, ‘Tarry ye; I perceive a fire; perhaps I can bring you some burning brand therefrom, or find some guidance at the fire.’ But when he came to the fire, a voice was heard: ‘O Moses! Verily I am thy Lord! Therefor (in My presence) put off thy shoes: thou art in the sacred valley Tuwa. I have chosen thee: Listen, then to the inspiration (sent to thee). Verily, I am Allah: there is no god but I: so serve thou Me (only), and establish regular prayer for celebrating My praise.” (Surah 20:9-14) (Emphasis mine)
Behold! Moses said to his family: ‘I perceive a fire; soon will I bring you from there some information, or I will bring you a burning brand to light our fuel, that ye may warm yourselves.’ But when he came to the (Fire), a voice was heard: ‘Blessed are those in the Fire and those around: and Glory to Allah, the Lord of the Worlds. O Moses! Verily, I am Allah, the Exalted in Might, the Wise…” (Surah 27:7-9) [Yusuf Ali and others mistranslate the verse at this point. An accurate translation of verse 8 is provided by Sher Ali: "So when he came to it, he was called by a voice, `Blessed is he who is in the fire and also those around it, and glorified be ALLAH, the Lord of the worlds'".] (Emphasis mine)
When Moses had fulfilled the term, and was travelling with his family, he perceived a fire in the direction of Mount Tur. He said to his family: ‘Tarry ye; I perceive a fire; I hope to bring you from there some information, or a burning firebrand, that ye may warm yourselves. But when he came to the (Fire), a voice was heard from the right bank of the valley, from a tree in hallowed ground: O Moses! Verily I am Allah, the Lord of the Worlds”…(Surah 28:29-30) (Emphasis mine)
The reason for this should be readily apparent: if Allah cannot enter into creation in order to speak with man, then Allah also cannot enter into creation to speak with the angels (and the Jinn also could not sneak into his presence in order to eavesdrop on Allah’s conversations with the angels). Although angels may be thought of as a different and higher order of being than man, since they are still creatures the distance between them and Allah is no less infinite. If the infinite cannot communicate with the finite, if Allah cannot enter into creation, then no degree of difference between men and angels, both of whom are finite, can overcome the qualitative difference between Allah and creatures, which, according to Muslims, prevents the former from communicating with the latter. All of this means that, if Allah is as the Qur’an claims him to be, i.e. a being who cannot enter into his creation, then the Qur’an cannot be what it claims to be, i.e. a revelation from Allah.
Muslims can only get out of this by dropping the notion that God cannot be absolute and also enter into his creation, but then they would not only have to find some way to scale those teachings in the Qur’an and the hadith that led them to this belief in the first place, they would also then have to concede that the incarnation cannot be ruled out on the basis of this principle. The difficulty of such a feat for Islamic theology and exegesis and the costliness of this for the Muslim polemic against Christianity would be just as monumental as it is necessary.