The greatest ayah — about the power of the Living Allah, whom neither drowsiness nor sleep overtakes. Whomever He guards, no jinn or human can harm.
ٱللَّهُ لَآ إِلَـٰهَ إِلَّا هُوَ ٱلْحَىُّ ٱلْقَيُّومُ ۚ لَا تَأْخُذُهُۥ سِنَةٌ وَلَا نَوْمٌ ۚ لَّهُۥ مَا فِى ٱلسَّمَـٰوَٰتِ وَمَا فِى ٱلْأَرْضِ ۗ مَن ذَا ٱلَّذِى يَشْفَعُ عِندَهُۥٓ إِلَّا بِإِذْنِهِۦ ۚ يَعْلَمُ مَا بَيْنَ أَيْدِيهِمْ وَمَا خَلْفَهُمْ ۖ وَلَا يُحِيطُونَ بِشَىْءٍ مِّنْ عِلْمِهِۦٓ إِلَّا بِمَا شَآءَ ۚ وَسِعَ كُرْسِيُّهُ ٱلسَّمَـٰوَٰتِ وَٱلْأَرْضَ ۖ وَلَا يَـُٔودُهُۥ حِفْظُهُمَا ۚ وَهُوَ ٱلْعَلِىُّ ٱلْعَظِيمُ
Allāh - there is no deity except Him, the Ever-Living, the Self-Sustaining. Neither drowsiness overtakes Him nor sleep. To Him belongs whatever is in the heavens and whatever is on the earth. Who is it that can intercede with Him except by His permission? He knows what is [presently] before them and what will be after them, and they encompass not a thing of His knowledge except for what He wills. His Kursī extends over the heavens and the earth, and their preservation tires Him not. And He is the Most High, the Most Great.
Allahu laaa ilaaha illaa Huwal Haiyul Qaiyoom; laa taakhuzuhoo sinatunw wa laa nawm; lahoo maa fissamaawaati wa maa fil ard; man zal lazee yashfa'u indahooo illaa bi-iznih; ya'lamu maa baina aydeehim wa mww khalfahum wa laa yuheetoona bishai'im min 'ilmihee illaa bimaa shaaa'; wasi'a Kursiyyuhus samaawaati wal arda wa laa ya'ooduho hifzuhumaa; wa Huwal Aliyyul 'Azeem