“If you are in doubt of what We have revealed to Our Messenger, then produce one chapter like it, call upon all your helpers, besides Allah, if you are truthful.” Surah al-Baqarah (The Heifer) 2: 23.
“Or do they say: “He (Prophet Muhammad, ) has forged it (this Qur’an)?” Nay! They believe not! Let them then produce a recitation like it (the Qur’an) if they are truthful.” Surah at-Toor (The Mount) 52: 33-34.
The challenge of the Quran, to create even a single chapter like it. To match its eloquence and grammar. Please enligthen me as to why this is impossible. Not being an arabic speaker i cannot speak to this. However i have read many books in english that are gramatically correct and very elegant in their use of language.