The Qur-an is not Divine but was authored by the Messenger of Allah, Muhammad صلى الله عليه وسلم

The Holy Qur-an is the Word of Allah and is the Book of Islam. It is the Prime source of the tenets and religious laws of Islam. It is also the source of its morals and ethics. The Qur-an is proved to be a Divine Revelation, which is free from all falsehood, there is no alternative but to believe in it.
                                                                                                                   
Anti-Islam forces have done their utmost to disprove the authenticity and Divine origin of the Qur-an from the first day of the beginning of its revelation. The Quraysh of Makkah challenged the Divine Revelation by claiming that it was written by the Messenger of Allah, Muhammad صلى الله عليه وسلم:

They also accused that the Qur-an was a copy of ancient tales that the Messenger of Allah, Muhammad صلى الله عليه وسلم has put together:

 The Quraysh of Makkah also accused that Muhammad صلى الله عليه was taught by a man:

They even alleged that the Qur-an was the work of a magician or a priest, in order to deny that it was a Divine Revelation inspired to Muhammad صلى الله عليه وسلم to guide mankind.
                                                                                                                   
A number of Orientalists who were biased against Islam supported the Pagan’s false accusations and made desperate attempts to convince the world that the Qur-an was not a Divine Revelation but had been contrived by Muhammad صلى الله عليه, blessings and peace be upon him. These Orientalists repeated the Pagans’ allegations despite the Qur-an’s authentic and conclusive proof to the contrary.
                                                                                                                   
Since Muhammad صلى الله عليه وسلم was illiterate he charged some of his companions to commit to writing the Divine Inspiration that was revealed to him. Had he been able to read and write, he would not have needed anybody to write down the verses that had been revealed to him. The allegations that he relied upon the Jewish and Christian scriptures in the Qur’an is not only false but is also ridiculous, for how could an illiterate person read, understand, and convey any beliefs existing in the Holy Books of other religions? How and when could that have happened? Such false allegations are not based upon any facts or proofs.
                                                                                                                   
Muhammad صلى الله عليه وسلم preached his Message in Makkah for about thirteen years, during which time there was no relationship between him and the Jews, and this fact is historically authenticated. His relationship with Christians has also been magnified beyond proportion. It has been related that when
Muhammad was about eleven years old, he traveled with his uncle Abu Talib in a caravan to Syria. During the short time that the caravan rested, Muhammad met Bahiri, a Christian monk, and talked to him for a few minutes. How could a boy of that age possibly comprehend the principle, rules, precepts, and fundamentals of a religion in a few minutes that Bahiri had talked to him? Also why did Bahiri the monk choose Muhammad صلى الله عليه وسلمout of all the people in the caravan to teach him the religion of Christianity? In addition to all this, why did
Muhammad صلى الله عليه وسلمwait for thirty years after his meeting with Bahiri before proclaiming his new faith? Such a story is not credible by any means.
                                                                                                                   
This matter led the Orientalist Huart to reject this story as being fabricated. He affirmed that not one of the Arabic documents and manuscripts that have been discovered, studied and published support this false allegation. He added: “ The role allegedly played by the Syrian Monk was nothing but the imagination of the author of the story” (Diraz, Muhammad Abdullah, An Introduction to the Qur’an, Dar Al-Qalam, Kuwait, 1971, p. 35, fn. (This book is one of the two scientific theses presented in French to Paris Universe, 1947).
                                                                                                                   
The Qur-an, in common with the Divine religions previously revealed, declared that there was one God, the Creator of the Universe and that all creatures are destined to return to Him. God Alone is the source of all Divine religions, so there should be no conflict in the fundamental precepts.
                                                                                                                   
The Qur-an, however, opposed many other prevalent beliefs among the followers of both Judaism and Christianity. This in itself is sufficient proof to refute the allegation that Muhammad referred to the Jewish and Christian sources of faith. Had that been the case, the difference in these beliefs would have been insignificant and would not have involved fundamental beliefs.
                                                                                                                   
No other scripture or Holy Book other than the Qur-an included scientific facts and cosmic and biological phenomenon in its verses more than fourteen centuries ago, all of which were discovered only in the fifties of the twentieth century. (Bucaille, Morris. The Qur’an, The Torah, The Gospel , and Science: A study of the Holy Books in the Light of Recent Progress in Science. Dar Al Ma’arif Publishing House, 1978)
                                                                                                                   
Following the advanced progress in all branches of science. Examples of this include the successive stages of the embryo and the fetus in the womb {a. The transformation from the sperm to the human form (23/14), b. Emigration of sex cells from the yolk sack to the loin}, the sun, the moon, the planets, the wind, rain etc. {a. Location of the stars (56/75), b. Expansion of the Universe. (51/47)}