The Reward of the Night Prayer
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 65
وَقَالَ رَسُولُ اَللَّهِ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ: «مَنْ كَثُرَ صَلاَتُهُ بِاللَّيْلِ حَسُنَ وَجْهُهُ بِالنَّهَارِ.
The Messenger of Allah صلى الله عليه وعلى آله وسلم said: "Whoever increases their prayers during the night will have a radiant face during the day."
- Ṣaḥīḥ al-Faqīh