The Qur'an is the True, Inimitable Word of Allah and It is a Miracle
The Qur'an has a miraculous nature that cannot be imitated. No one can produce anything similar to the Qur'an, nor ten Surahs or even one Surah like it. The eloquence, clarity, precision and grace of the Qur'an cannot be but from Allah. The great and abundant principles and meanings within the Qur'an -- which are of great benefit in this world and for the Hereafter -- cannot be but from Allah. There is nothing like His High Self and Attributes or like His sayings and actions. Therefore His Words are not like the words of His creatures. This is why Allah said:
وما كان هذا القرآن أن يفترى من دون الله
And this Qur'an is not such as could ever be produced by other than Allah.
meaning, a book like this cannot be but from Allah. This is not similar to the speech uttered by humans.
ولكن تصديق الذي بين يديه
but it is a confirmation of (the revelation) which was before it,
Such as previous revelations and Books. The Qur'an confirms these books and is a witness to them. It shows the changes, perversions and corruption that have taken place within these Books.
Then Allah said,
وتفصيل الكتاب ﻻ ريب فيه من رب العالمين
and a full explanation of the Book -- wherein there is no doubt -- from the Lord of all that exists.
That is, fully and truly explaining and detailing the rules and the lawful and the unlawful. With this complete and more than sufficient explanation, the Qur'an leaves no doubt that it is from Allah, the Lord of all that exists.
Allah says,