Quran 7:187

They ask you [Prophet] about the Hour, ‘When will it happen?’ Say, ‘My Lord alone has knowledge of it: He alone will reveal when its time will come, a time that is momentous in both the heavens and earth. All too suddenly it will come upon you.’ They ask you about it as if you were eager [to find out]. Say, ‘God alone has knowledge of [when it will come], though most people do not realize it.’