Surah Al-A'raf 7:187

يَسْـَٔلُونَكَ عَنِ ٱلسَّاعَةِ أَيَّانَ مُرْسَىٰهَا ۖ قُلْ إِنَّمَا عِلْمُهَا عِندَ رَبِّى ۖ لَا يُجَلِّيهَا لِوَقْتِهَآ إِلَّا هُوَ ۚ ثَقُلَتْ فِى ٱلسَّمَـٰوَٰتِ وَٱلْأَرْضِ ۚ لَا تَأْتِيكُمْ إِلَّا بَغْتَةً ۗ يَسْـَٔلُونَكَ كَأَنَّكَ حَفِىٌّ عَنْهَا ۖ قُلْ إِنَّمَا عِلْمُهَا عِندَ ٱللَّهِ وَلَـٰكِنَّ أَكْثَرَ ٱلنَّاسِ لَا يَعْلَمُونَ

They ask you, [O Muḥammad], about the Hour: when is its arrival? Say, "Its knowledge is only with my Lord. None will reveal its time except Him. It lays heavily upon the heavens and the earth. It will not come upon you except unexpectedly." They ask you as if you are familiar with it. Say, "Its knowledge is only with Allāh, but most of the people do not know."

Translation: Saheeh International

Tafsir

They that is the people of Mecca will question you about the Hour the Resurrection when it shall come to pass. Say to them ‘The knowledge of when it shall be is only with my Lord. He alone shall reveal it manifest it at its proper time li-waqtihā the lām here functions as fī ‘at’. …

Excerpt from Tafsir al-Jalalayn, commentary on 7:187, via Quran.com. The reader has the full commentary and 9 more tafsirs.