(Al-Hajj) 22 : 55
وَلَا يَزَالُ الَّذِينَ كَفَرُوا فِي مِرْيَةٍ مِنْهُ حَتَّىٰ تَأْتِيَهُمُ السَّاعَةُ بَغْتَةً أَوْ يَأْتِيَهُمْ عَذَابُ يَوْمٍ عَقِيمٍ
And those who disbelieved will not be removed from the doubt of it until the Hour comes upon them unexpectedly or there comes to them the punishment of a barren Day.
The Arabic Quran reading Fujjar will only clear their doubt when they are being killed by the other people belonging to Messenger’s community after the second coming of Jesus as told in verse 38: 8. See explanation 11: 17; 13: 30-31 and 15: 99.