Allamah Shibli Naumani (RA) [1857-1914] has mentioned this incident and attested to its authenticity in his book, "Ilm-Kalam" the history of Muslim theology.
During the reign of Khalif Al-Ma'moon [786-833] non-Muslims were beginning to cast doubts upon the authenticity of Qur'aan and they were given some free reign in the court of the Muslim caliph. One day the foremost experts of Arabic (egyptian non Muslims) raised objections to the use of certain Arabic terms and lexicons in the court. The Master of Kalam Shaykh Nizam (RA) was present at the court. He heard the objections patiently and then asked should he respond to these objections serially or give a general reply to all of them.
The objectors asked for one response for all objections.
Shaykh Nizam (RA) asked, “Do you admit that Makkah was filled with foremost experts of Arabic language when the Qur’aan was being revealed?”
They replied in the affirmative.
Shaykh Nizam (RA) asked, “Do you accept that the Non-Muslims of Makkah tried their utmost and left no stone unturned in their opposition to Islam and the Qur’aan?”
They replied in the affirmative.
Shaykh Nizam (RA) responded, “None of the objections which you have outlined were EVER raised by anyone of them!”
