This everlasting miracle is the Book of Allah and His Revealed Speech that:
Falsehood cannot approach it from before it or from behind it. (41:42)
Allah, The Almighty, Confirms this fact, when He Says (what means):
And if any one of the polytheists seeks your protection, then grant him protection so that he may hear the Words of Allah. (9:6)
Those who remained behind will say when you set out toward the war booty to take it, “Let us follow you.” They wish to change the Words of Allah. (48:15)
Those two verses prove that the Quran is the Words and Speech of Allah, that He Has Revealed to His Prophet Muhammad.
Jaabir ibn ‘Abdullah reported that the Prophet used to invite people to Islam during the Hajj season and would say:
“Who are willing to give me asylum so that I can convey the Speech of my Lord, for the Quraysh have prevented me from conveying the Speech of my Lord.” (At-Tirmidhi and Ahmad)
Hence, it is the Speech of Allah as unanimously agreed upon by all Muslims.
This fact is supported by several logical and tangible pieces of evidence including the following:
1- The polytheists failed to produce a single verse, let alone a single Chapter, or a book like the Quran despite the fact that they were utterly determined and extremely motivated to oppose and falsify the call of the Prophet.
Furthermore, we must remember that they were the masters of the Arabic language, in which the Quran was revealed.
Certainly, this constitutes a definitive proof that the Quran is from Allah, The Lord of The Worlds.
2- The Quran foretold many matters of the unseen and made several prophecies that were all fulfilled exactly as they were foretold.
For example, the Persians defeated the Byzantines in one of their battles. The Quran recorded this defeat foretelling that the Byzantines would defeat the Persians, and this is what actually happened.
Allah, The Exalted, Says (what means):
The Byzantines have been defeated * In the nearest land. But they, after their defeat, will overcome. * Within three to nine years. (30: 2-4)
3- The Quran includes many miraculous scientific facts that were only discovered fourteen centuries later.
For example, the Quran told us about a barrier separating the salty water from the fresh water not to mix with each other. Allah, The Exalted, Says (what means):
He Released the two seas, meeting [side by side]; * Between them is a barrier [so] neither of them transgresses. (55:19-20)
After about fourteen centuries, modern science confirmed this scientific fact.
4- When one reads the Book of Allah, he goes into a state of peace and tranquility unlike the human speeches or writings.
Allah says (what means):
Those who have believed and whose hearts are assured by the remembrance of Allah. Unquestionably, by the remembrance of Allah hearts are assured.” (13:28)
5- The Quran is also a cure and it expels the devils when it is recited. Allah, The Almighty, says (what means):
And We send down of the Quran that which is healing and mercy for the believers… (17:82)
Of course, it’s to list all the evidences that prove the Quran is the Speech of Allah in one article. Al-Waleed ibn Al-Mugheerah, one of the senior leaders of the polytheists of Quraysh, said about the Quran:
THE QURAN – THE WORD OF GOD
This is the Quran, the Speech of Allah that has been challenging humankind and proving its inability to produce something to its effect as to its eloquence, wise judgments, and authentic news.
The challenge is still valid, and the inability of mankind to face that challenge remains. Thus, the Quran will remain the everlasting Argument of Allah, The Almighty, against all opponents and disbelievers.