وَلَوْ أَنَّ قُرْءَانًا سُيِّرَتْ بِهِ ٱلْجِبَالُ أَوْ قُطِّعَتْ بِهِ ٱلْأَرْضُ أَوْ كُلِّمَ بِهِ ٱلْمَوْتَىٰ بَل لِّلَّهِ ٱلْأَمْرُ جَمِيعًا
"If by a Qurʾān the mountains were made to move, or the earth were torn open, or the dead were made to speak (they still would not believe). No — the whole affair belongs to God."
The verse answers the demand for a miracle, and the form of the answer must be recorded: three extraordinary events are enumerated and the sentence is cut off before it is completed (bal li'llāhi'l-amru jamīʿā).
The lexicographers record this cutting off (ḥadhf) and supply the rest of the unfinished sentence from the context: "they still would not believe."
I record this as an observation about the word order: that the consequence is left unsaid is itself the answer. And the same demand was treated at al-Furqān 25/21 (law lā unzila ʿalayna'l-malāʾika); al-Kahf 18/57 was on the same line. I rely on that treatment.