Concise Quran Commentary
Allah subjugated the sun and the moon to continuously orbit. He subjugated the day and the night to alternate, the night for your sleep and rest and the day for your activity and work.
وَسَخَّرَ لَكُمُ ٱلشَّمْسَ وَٱلْقَمَرَ دَآئِبَيْنِ ۖ وَسَخَّرَ لَكُمُ ٱلَّيْلَ وَٱلنَّهَارَ
He has made the sun and the moon for your service, both constant in their courses, and has made for you the night and the day[23].