Surah 17 : Ayah 12

وَجَعَلْنَا ٱلَّيْلَ وَٱلنَّهَارَ ءَايَتَيْنِ ۖ فَمَحَوْنَآ ءَايَةَ ٱلَّيْلِ وَجَعَلْنَآ ءَايَةَ ٱلنَّهَارِ مُبْصِرَةً لِّتَبْتَغُوا۟ فَضْلًا مِّن رَّبِّكُمْ وَلِتَعْلَمُوا۟ عَدَدَ ٱلسِّنِينَ وَٱلْحِسَابَ ۚ وَكُلَّ شَىْءٍ فَصَّلْنَـٰهُ تَفْصِيلًا

We have made the day and night as two signs. We darkened the night and made the day bright, so that you may seek your Lord’s bounty and know the number of years and calculation [of time]. And We have expounded everything in detail.