Surat Al-'Isrā' - سورة الإسراء

وَجَعَلْنَا اللَّيْلَ وَالنَّهَارَ آيَتَيْنِ ۖ فَمَحَوْنَا آيَةَ اللَّيْلِ وَجَعَلْنَا آيَةَ النَّهَارِ مُبْصِرَةً لِّتَبْتَغُوا فَضْلًا مِّن رَّبِّكُمْ وَلِتَعْلَمُوا عَدَدَ السِّنِينَ وَالْحِسَابَ ۚ وَكُلَّ شَيْءٍ فَصَّلْنَاهُ تَفْصِيلًا

Muhsin Khan: And We have appointed the night and the day as two Ayat (signs etc.). Then, We have made dark the sign of the night while We have made the sign of day illuminating, that you may seek bounty from your Lord, and that you may know the number of the years and the reckoning. And We have explained everything (in detail) with full explanation.