Surah Al-Hadid — Ayah 6 (57:6)
يُولِجُ ٱلَّيۡلَ فِي ٱلنَّهَارِ وَيُولِجُ ٱلنَّهَارَ فِي ٱلَّيۡلِۚ وَهُوَ عَلِيمُۢ بِذَاتِ ٱلصُّدُورِ ٦
English translation (Saheeh International)
He causes the night to enter the day and causes the day to enter the night, and He is Knowing of that within the breasts.
Brief commentary
He enters the night into the day and so the darkness arrives and people sleep; He enters the day into the night and so the light arrives and people go about their business. He is aware of everything that the hearts of His servants contain; none of it is hidden from Him.