He revealed that only Allah has Knowledge of the Hour

one of people's main concerns is the time and the hour of the day of judgment. yet, allah has revealed that none but he can know of it, and commanded the prophet (saas) to give the following answer if asked about it:

people will ask you about the last hour. say: "only allah has knowledge of it. what will make you understand? it may be that the last hour is very near." (surat al-ahzab: 63)

say: "i do not know whether what you are promised is close or whether my lord will appoint a longer time before it." (surat al-jinn: 25)

if they turn their backs, then say: "i have informed all of you equally and i do not know if what you have been promised is near or far." (surat al-anbiya': 109)