فَإِذَا قَضَيۡتُمُ ٱلصَّلَوٰةَ فَٱذۡكُرُواْ ٱللَّهَ قِيَٰمٗا وَقُعُودٗا وَعَلَىٰ جُنُوبِكُمۡۚ فَإِذَا ٱطۡمَأۡنَنتُمۡ فَأَقِيمُواْ ٱلصَّلَوٰةَۚ إِنَّ ٱلصَّلَوٰةَ كَانَتۡ عَلَى ٱلۡمُؤۡمِنِينَ كِتَٰبٗا مَّوۡقُوتٗا

Fa izaa qadaitumus Salaata fazkurul laaha qiyaamanw wa qu'oodanw wa 'alaa junoobikum; fa izatma'nantum fa aqeemus Salaah; innas Salaata kaanat 'alal mu'mineena kitaabam mawqootaa

When ye pass (Congregational) prayers, celebrate Allah's praises, standing, sitting down, or lying down on your sides; but when ye are free from danger, set up Regular Prayers: For such prayers are enjoined on believers at stated times.

— An-Nisa' (ٱلنِّسَاء), 4:103