He asks:"When will be this Day of Resurrection"meaning, he says when will the Day of Judgement be His question is only a question of denying its occurrence, and rejecting its existence.This is as Allah says,وَيَقُولُونَ مَتَى هَـذَا الْوَعْدُ إِن كُنتُمْ صَـدِقِينَ قُل لَّكُم مِّيعَادُ يَوْمٍ لاَّ تَسْتَـَخِرُونَ عَنْهُ سَاعَةً وَلَا تَسْتَقْدِمُونَAnd they say:"When is this promise if you are truthful"Say:"The appointment to you is for a Day, which you cannot put back for an hour nor put forward." (34:29-30)Here Allah says,فَإِذَا بَرِقَ الْبَصَرُ