فَاِذَا قَضَيْتُمُ الصَّلٰوةَ فَاذْكُرُوا اللّٰهَ قِيَامًا وَّقُعُوْدًا وَّعَلٰى جُنُوْبِكُمْ ۚ فَاِذَا اطْمَأْنَنْتُمْ فَاَقِيْمُوا الصَّلٰوةَ ۚ اِنَّ الصَّلٰوةَ كَانَتْ عَلَى الْمُؤْمِنِيْنَ كِتٰبًا مَّوْقُوْتًا ( النساء: ١٠٣ )
Fa izaa qadaitumus Salaata fazkurul laaha qiyaamanw wa qu'oodanw wa 'alaa junoobikum; fa izat maanantum fa aqeemus Salaah; innas Salaata kaanat 'alal mu'mineena kitaabam mawqootaa (an-Nisāʾ 4:103)
Sahih International:
And when you have completed the prayer, remember Allah standing, sitting, or [lying] on your sides. But when you become secure, re-establish [regular] prayer. Indeed, prayer has been decreed upon the believers a decree of specified times. (An-Nisa [4] : 103)
1 Mufti Taqi Usmani
Once you have finished your Salāh, then, remember Allah while standing, sitting and reclining. As soon as you are secure, perform Salāh as due. Surely, Salāh is an obligation on the believers that is tied up with time.