And if they do not respond to you - then know that it [i.e., the Qur’ān] was revealed with the knowledge of Allāh1 and that there is no deity except Him. Then,2 would you [not] be Muslims?
Translation: Saheeh International (English)
1 i.e., that knowledge which no one possesses except Him (subḥānahu wa taʿālā).
If they do not bring what the Messenger challenges them to – and they are unable to do it! – then the believers should know with certainty that the Qur’ān is revealed from Allah by His knowledge to His Messenger, and that it is not fabricated, and that there is no true god except for Him. Allah asks whether you surrender to Him in devotion after these conclusive proofs?