The Heights - 7:187
"They ask you when that Hour (the end of the world) will come. Say: "The knowledge of it is with my Lord". None reveals it except Him when its time comes. That Hour which weighs heavily on the heavens and the earth will come to you suddenly. They ask you as if you are aware of it. Say, "With Allah is its knowledge."But most of the people do not know."
Related:
The Jinn/72:25
"Say, "I do not know whether what you have been promised is near or whether my Lord has appointed for it a long time."
The Coalition/33:63
"The people ask you about the Hour (the last hour of the world). Say, "The knowledge of it is with Allah; how do you know, perhaps the Hour is near."
Those Who Pull Out/79:42
They ask you when the Hour (the end of the world) will take place.
Those Who Pull Out/79:43
It is not for you (O Muhammad) to declare it.
Those Who Pull Out/79:44
Its decision belongs to your Lord.