Quran 57:6 from Surah Al-Hadid on Divine Marvels.
يُولِجُ ٱلَّيۡلَ فِي ٱلنَّهَارِ وَيُولِجُ ٱلنَّهَارَ فِي ٱلَّيۡلِۚ وَهُوَ عَلِيمُۢ بِذَاتِ ٱلصُّدُورِ
English translation: He merges the night into the day and He merges the day into the night and He (is) All-Knower of what is in the breasts of what is in the breasts
Transliteration: yuliju al-layla fi al-nahari wayuliju al-nahara fi al-layli wahuwa alimun bidhati al-suduri