Those Who were given Knowledge before truly admit the Qur'an
Allah says to His Prophet Muhammad ﷺ:
قُلْ
(Say) O Muhammad to these disbelievers concerning what you have brought to them of this Glorious Qur'an:
ءَامِنُواْ بِهِ أَوْ لاَ تُؤْمِنُواْ
("Believe in it (the Qur'an) or do not believe (in it).) meaning, it is all the same whether you believe in it or not, for it is true in and of itself. It was revealed by Allah, Who mentioned it previously in the Books that He revealed to other Messengers. Hence He says:
إِنَّ الَّذِينَ أُوتُواْ الْعِلْمَ مِن قَبْلِهِ
(Verily, those who were given knowledge before it,) meaning righteous people among the People of the Book, who adhered to their Books and appreciated them without distorting them.
The first verse (101): وَلَقَدْ آتَيْنَا مُوسَىٰ تِسْعَ آيَاتٍ mentions the bestowal of nine clear signs on Sayyidna Musa (علیہ السلام) . The word: آیَہ ('ayah) carries the meaning of miracle or sign as well as that of the آیَت : ayat or verses of the Qur'an, that is, the divine injunctions. At this place, the probability of both meanings exists. Therefore, a number of commentators have taken the word 'ayat' to mean miracles - and the number nine does not make it necessary that they will not be more than nine - but, at this place, the figure 'nine' has been mentioned on the basis of some particular importance it has. Sayyidna ` Abdullah ibn ` Abbas ؓ has enumerated these miracles as follows:
The Quran is a declaration of pristine truth. But this pristine truth is what is least acceptable to man. For this reason God did not burden the preacher of truth with the responsibility of forcing people to believe in him. All that is desired of him is that he should communicate the truth to the addressee to the fullest possible extent. The Quran makes full allowances for the weaknesses of the addressees. Hence the Quran has been revealed at intervals, so that those who are serious about it, may have time to fully understand it; slowly and steadily it may become a part and parcel of their thoughts and actions.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.