Quran 45:32

وَإِذَا قِيلَ إِنَّ وَعۡدَ ٱللهِ حَقٌّ۬ وَٱلسَّاعَةُ لَا رَيۡبَ فِيہَا قُلۡتُم مَّا نَدۡرِى مَا ٱلسَّاعَةُ إِن نَّظُنُّ إِلَّا ظَنًّ۬ا وَمَا نَحۡنُ بِمُسۡتَيۡقِنِينَ ٣٢

When it is proclaimed that ALLAH’s promise is the truth and that the Hour (of Judgment) is inevitable, you said, "We do not know what the Hour is! We are full of conjecture about it; we are not certain."