Being complete true revelation, the Qur'an is itself a miracle. As it is authentically known and also was mentioned in the above, at the time of the Qur'an's revelation the literary talent and eloquence of Arabs were at their peak, yet the miraculousness of the Qur'an is not confined to its inimitable literary excellence and eloquence. It stands on its own innumerous different merits some of which are beyond the reach of the complete conception of the literary geniuses of the Arab world. It has such a rhetorical capacity and linguistic excellence that is able to express different views and knowledge in a manner that is understood and appreciated by every rational human being of any standard and accomplishment of all the ages. Then everybody in any time, once provided with the opportunity to become acquainted with the Holy Qur'an, which offers information by which all of his/her arguments will be completed, he/she can find himself or herself convinced by it. Such extensive knowledge and such power of expression is beyond the limitations of human ability. Even of the literate Arab people, as were previously referred to, especially at the time of the Qur'an's revelation when the literature of the Arabic language had reached its climax, none dared to bring a Sura similar to even its shortest one. This very single point is the smallest miraculous aspect of the Qur'an.
There is no doubt that if the Qur'an were the word of a human and the Prophet (p.b.u.h.), himself, who was known to the world as an illiterate one, had produced it, they would bring many Qur'ans like it and would prove that this is not the word of Allah revealed to him (p.b.u.h.). In that condition, the enemies of Islam would maintain their works which would be available everywhere and in any ages so that they could publish and distribute them, even now, to defame the one genuine Qur'an, but there is none.
Apart from its inimitable literary excellence, the Holy Qur'an with its other names such as 'Furqan' and 'Tibyan' referring to the abilities it has, presents to the human world definite prophecies fulfilled and yet to be fulfilled, and long after. It contains some facts about endowments in nature which the human knowledge of science as it progresses will have to understand, for its further advancement. The perfectness of such nature, naturally, will be the last word with regard to the ideas, religious and social laws, sciences, and many many other things that it contains and will remain for ever, until the Hereafter.
This universality of the truth expressed in the idea and beauty and the attractive force of the language is so divine that, as we said before, it is beyond the reach of the expressive power of any limited being. It is in this regard that the Holy Qur'an claims to be not only the word of Allah, inimitable, but the Final Word in respect to truth and justice the better or even the like of it is impossible to be produced by any one.
However, it is true to say simply and shortly that the Holy Qur'an is a miracle with respect to its contents which is the source of all knowledge and science, as it itself says : " Say : If the sea were ink (wherewith to write out) for the words of my Lord, the sea would surely be consumed before the words of my Lord are exhausted, though We were to bring the like of that (sea) to add thereto for its aid", (Sura Al-Kahf, No. 18, verse 109).
Thus, this verse, by itself, is a vital piece of evidence regarding the correctness of the above stated claim. (1)
source : http://www.maaref-foundation.com