Tafsir of Ar-Rum 30:23

ومن آياته منامكم بالليل والنهار وابتغاوكم من فضله

And among His signs is your sleep by night and by day, and your seeking of His bounty. Among His signs is the cycle of sleep that He has created during the night and the day, when people are able to cease moving and rest, so that their tiredness and exhaustion will go away. And He has enabled you to seek to earn a living and to travel about during the day, this is the opposite of sleep.

إن في ذلك ﻻيات لقوم يسمعون

Verily, in that are indeed signs for a people who listen. meaning, understand