وَقَالُوا يَا أَيُّهَا الَّذِي نُزِّلَ عَلَيْهِ الذِّكْرُ إِنَّكَ لَمَجْنُونٌ (6)
(15:6) They say, "You, upon whom the Divine word *3 has been sent down, are surely insane.
*3) The word (Zikr) literally means "to cause to remember, "to caution" and "to give advice". But the Qur'an has used it as a technical term for "Admonition", which comes as a precept. Thus all the Books that had been sent down to the Messengers were Zikr, and the Qur'an is also Zikr.