Quran 4:103 from Surah An-Nisaa on Divine Marvels.
فَإِذَا قَضَيۡتُمُ ٱلصَّلَوٰةَ فَٱذۡكُرُواْ ٱللَّهَ قِيَٰمٗا وَقُعُودٗا وَعَلَىٰ جُنُوبِكُمۡۚ فَإِذَا ٱطۡمَأۡنَنتُمۡ فَأَقِيمُواْ ٱلصَّلَوٰةَۚ إِنَّ ٱلصَّلَوٰةَ كَانَتۡ عَلَى ٱلۡمُؤۡمِنِينَ كِتَٰبٗا مَّوۡقُوتٗا
English translation: Then when you (have) finished the prayer then remember Allah standing and sitting and (lying) on your sides But when you are secure then establish the (regular) prayer Indeed the prayer is on the believers prescribed (at) fixed times
Transliteration: fa-idha qadaytumu al-salata fa-udh'kuru al-laha qiyaman waqu'udan wa'ala junubikum fa-idha it'manantum fa-aqimu al-salata inna al-salata kanat ala al-mu'minina kitaban mawqutan