An-Nisa 4:103
فَإِذَا قَضَيْتُمُ ٱلصَّلَوٰةَ فَٱذْكُرُوا۟ ٱللَّهَ قِيَـٰمًا وَقُعُودًا وَعَلَىٰ جُنُوبِكُمْ ۚ فَإِذَا ٱطْمَأْنَنتُمْ فَأَقِيمُوا۟ ٱلصَّلَوٰةَ ۚ إِنَّ ٱلصَّلَوٰةَ كَانَتْ عَلَى ٱلْمُؤْمِنِينَ كِتَـٰبًا مَّوْقُوتًا
Fa-itha qadaytumu assalatafathkuroo Allaha qiyaman waquAAoodanwaAAala junoobikum fa-itha itma/nantumfaaqeemoo assalata inna assalatakanat AAala almu/mineena kitaban mawqoota
"And when you have completed the prayer, remember Allāh 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, translation by Sahih International
A short reflection
Prayer is prescribed at fixed times — not left to mood, so mood cannot take it from us.