(Ad-Dukhan) 44 : 50
إِنَّ هَٰذَا مَا كُنْتُمْ بِهِ تَمْتَرُونَ
Indeed, this is what you used to doubt.
After receiving Adhikr—the Confirming Truth—the Fujjar who do not confirm that he is a believer destined to Paradise, are in doubt regarding unseen things which Adhikr predicts, and they are destined to be filled in Hell. See explanation 2:147-148; 32:20; and 42:14.