28:73
وَمِن رَّحْمَتِهِۦ جَعَلَ لَكُمُ ٱلَّيْلَ وَٱلنَّهَارَ لِتَسْكُنُوا۟ فِيهِ وَلِتَبْتَغُوا۟ مِن فَضْلِهِۦ وَلَعَلَّكُمْ تَشْكُرُونَ
wamin raḥmatihi jaʿala lakumu al-layla wal-nahāra litaskunū fīhi walitabtaghū min faḍlihi walaʿallakum tashkurūna
In His mercy He has given you night and day, so that you may rest and seek His bounty and be grateful.’
It is out of His Mercy that He has made for you the night and the day that you may rest therein (i.e. during the night) and that you may seek of His Bounty (i.e. during the day) - and in order that you may be grateful.