the holy quran is neither a poem nor a work of prose with rhymes. it is in its own right an unprecedented and divine text. for this reason, the arabs were awestruck by the quran since such a written work was unprecedented; they were left with no other choice but to claim that the quran was full of magic.
to date, poets and men of letters have been amazed by the verses and the meanings in the quran and are left without recourse, unable to utter a single word equivalent to one single verse of the quran. it is concise and to the point, and its rhetoric does not resemble that of any person. if a single word were to be removed or added, the perfection of the eloquence of the quran would be destroyed.
there are two elements to the conciseness of the holy quran, both of which rely on revelation: its verse and its meaning.
the most apparent evidence of the miraculous status of the quran is its lofty rhetoric. allah defies all the masters of rhetoric in his divine book in such a way that this challenge encompasses all times and places and no one is able to utter a word that is equivalent to that of the holy quran. those who have attempted to do so have always failed. as this has not been done until now, it must be impossible to do so at any time. (the verses which prove the statements of this issue are al-baqarah 23-24, al-isra 88, al-hud 13-14, al-yunus, 38)
it should be noted that the rhetorical challenge of the quran was directed towards those who had the utmost eloquence in the arabic language.
prophet muhammad was  illiterate
prophet muhammad (pbuh) could neither read, nor write. the fact that the words of preceding prophets and events in societies and people far from his milieu were depicted in the quran is nothing short of a miracle.
the quraishis knew that muhammad was illiterate. how could he possibly have learned the historical accounts and incidents related to previous societies and prophets? this had to be divine revelation itself.
"and thou wast not (able) to recite a book before this (book came), nor art thou (able) to transcribe it with thy right hand: in that case, indeed, would the talkers of vanities have doubted." (al-ankabut, 48)
prophet muhammad not only spoke of incidents related to previous prophets and societies, but he also informed people of incidents that were to happen in the future.
the most important of these incidents occurred when muhammad informed the people that the fire-worshipping persians, who had defeated the byzantines, would be defeated in a short period of time and that the byzantine state would become triumphant. at that time such a thing was considered a remote possibility; however, incidents turned out as allah had foretold in the quran and in less than ten years the byzantines were triumphant over the persians:
"alif lam mim. the roman empire has been defeated- in a land close by; but they, (even) after (this) defeat of theirs, will soon be victorious- within a few years. with allah is the decision, in the past and in the future: on that day shall the believers rejoice- with the help of allah. he helps whom he will, and he is exalted in might, most merciful. " (ar-rum, 1-5)
allah announced that his prophet  would  conquer  mecca
according to an account, before heading to hudaybiyah, the prophet (pbuh) had a dream in which he and his companions shaved their heads and entered mecca in victory; later he told his companions about this dream. they were very pleased when they heard this. finally they set out on the campaign to hudaybiyah, but after an initial defeat, they returned in disappointment. some hypocrites also started to spread negative rumor about the incident.  in response to this, allah informed people on the conquest to come by reference to the conquest of khaybar a year ago.
"truly did allah fulfill the vision for his messenger. ye shall enter the sacred mosque, if allah wills, with minds secure, heads shaved, hair cut short, and without fear. for he knew what ye knew not, and he granted, besides this, a speedy victory."(al-fath, 27 )
many religious  beliefs, practices  and  moral issues  that  were unknown to the arabs are described  in the quran.
the arabs were unaware of the tenets of monotheism, the need to believe in angels, prophesies, the day of judgment, heaven and hell in return for worldly deeds and provisions related to laws, halal and haram, the codes of conduct for ensuring human happiness, the spirit of brotherhood and helping one another, justice and fear of allah, or their duties towards their families and society. the prophet would read the revelations related to these rules, essential to the lives of humans, and would convey them to society. he was illiterate. he knew neither jurisprudence, sociology, psychology nor had he acquired education on subjects related to philosophy, ethics and prophesies. that he counseled on such matters proved that his prophethood was revealed unto him alone from the divine treasure.