Al-Isra' - ১৭:১২

وَجَعَلْنَا اللَّيْلَ وَالنَّهَارَ آيَتَيْنِ فَمَحَوْنَا آيَةَ اللَّيْلِ وَجَعَلْنَا آيَةَ النَّهَارِ مُبْصِرَةً لِتَبْتَغُواْ فَضْلاً مِّن رَّبِّكُمْ وَلِتَعْلَمُواْ عَدَدَ السِّنِينَ وَالْحِسَابَ وَكُلَّ شَيْءٍ فَصَّلْنَاهُ تَفْصِيلاً
[17:12]
And We have made the night and the day two signs, then We have made the sign of the night to pass away and We have made the sign of the day manifest, so that you may seek grace from your Lord, and that you might know the numbering of years and the reckoning; and We have explained everything with distinctness.
We have made the Night and the Day as two (of Our) Signs: the Sign of the Night have We obscured, while the Sign of the Day We have made to enlighten you; that ye may seek bounty from your Lord, and that ye may know the number and count of the years: all things have We explained in detail.
And We appoint the night and the day two portents. Then We make dark the portent of the night, and We make the portent of the day sight-giving, that ye may seek bounty from your Lord, and that ye may know the computation of the years, and the reckoning; and everything have We expounded with a clear expounding.