The Request of the Polytheists for Proofs while the Qur'an is itself a Proof
Allah, the Exalted, informs about the disbelievers in their statement,
وَقَالُوا لَوْلَا يَأْتِينَا بِأيَةٍ مِّن رَّبِّهِ
They say;"Why does he not bring us a Sign from His Lord?"
This means, `Why doesn't Muhammad bring us some proof from his Lord?' They meant a sign that was proof of his truthfulness in his claim that he was the Messenger of Allah.
Allah, the Exalted, said,
أَوَلَمْ تَأْتِهِم بَيِّنَةُ مَا فِي الصُّحُفِ الاُْولَى
Has there not come to them the proof of that which is in the former papers (Scriptures)!
This means the Qur'an which Allah revealed to him while he was an unlettered man who could not write well and who did not study with the People of the Book. Yet, the Qur'an contains information about the people of the past that tells of their events from times long ago and it agrees with the authentic information in the previous Books concerning these matters. The Qur'an is the supervisor of these other Books. It verifies what is correct and explains the mistakes that were falsely placed in these Books and attributed to them.
This Ayah is similar to Allah's statement in Surah Al-`Ankabut,
وَقَالُواْ لَوْلَا أُنزِلَ عَلَيْهِ ءايَـتٌ مِّن رَّبِّهِ قُلْ إِنَّمَا الاٌّيَـتُ عِندَ اللَّهِ وَإِنَّمَأ أَنَاْ نَذِيرٌ مُّبِينٌ
أَوَلَمْ يَكْفِهِمْ أَنَّأ أَنزَلْنَا عَلَيْكَ الْكِتَـبَ يُتْلَى عَلَيْهِمْ إِنَّ فِى ذلِكَ لَرَحْمَةً وَذِكْرَى لِقَوْمٍ يُوْمِنُونَ
And they say;"Why are not signs sent down to him from his Lord!"
Say;"The signs are only with Allah, and I am only a plain warner."
It is not sufficient for them that We have sent down to you the Book which is recited to them! Verily, herein is mercy and a reminder for a people who believe. (29;50-51)
In the Two Sahihs, it is recorded that the Messenger of Allah said,
مَا مِنْ نَبِيَ إِلاَّ وَقَدْ أُوتِيَ مِنَ الاْاياتِ مَا امَنَ عَلَىىِمثْلِهِ الْبَشَرُ وَإِنَّمَا كَانَ الَّذِي أُوتِيتُهُ وَحْيًا أَوْحَاهُ اللهُ إِلَيَّ فَأَرْجُو أَنْ أَكُونَ أَكْثَرَهُمْ تَابِعًا يَوْمَ الْقِيَامَة
There was not any Prophet except that he was given signs that caused men to believe. That which I have been given is a revelation that Allah has revealed to me, so I hope that I have the most followers among them (the Prophets) on the Day of Resurrection.
In this Hadith, the Prophet only mentioned the greatest of the signs that he was given, which is the Qur'an. However, he did have other miracles, which were innumerable and limitless. These miracles have all been recorded in the books that discuss them, and they have been affirmed in the places that mention them.
Then Allah says