Rev. Prof. Dr. F.N. Lee:
“Now the A.D. 609-680 Qur’an frequently tries to shame the “People of the Book” – viz. especially the Judaists, but also the Christians – for not heeding the Holy Bible. In so doing, it is true that Muhammad was hereby trying to establish the superiority of the Qur’an.
But by rebuking the majority of Judaists and Christians for not being loyal to the Bible, he established the veracity of the Bible. And in conceding that some of the “People of the Book” were indeed quite loyal to it – he unwittingly thereby confirmed the accessibility and authority and understandability thereof also in his own day and age and locality.
Thereby Muhammad himself overthrows the later Islamic theory that the Holy Bible had long been corrupted and was insufficiently intelligible by the time of the beginning and the duration and the completion of the compilation of the Qur’an.”
Source: “Bible and Qur’an: The Reliability of the Original Bible and the Original Qur’an,” pages 22-23, available free online here: http://www.dr-fnlee.org/bible-and-quran-the-reliability-of-the-original-bible-and-the-original-quran/