Verse 12

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

And We rendered the night and the day as two signs as We turn the night sign into the day sign, bright, that you may seek the provisions of your Lord and in order to teach you counting of the years as well as calculus. And We described everything in full detail.