﴿ ٱلَّذِينَ يَخْشَوْنَ رَبَّهُم بِٱلْغَيْبِ وَهُم مِّنَ ٱلسَّاعَةِ مُشْفِقُونَ ﴾

“who stand in awe of their Sustainer although He is beyond the reach of human perception, and who tremble at the thought of the Last Hour.”

Please check ayah 21:50 for complete tafsir.