Congregational Prayer and Its Virtue
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 57
وَقَالَ اَلصَّادِقُ عَلَيْهِ اَلسَّلاَمُ: «مَنْ صَلَّى اَلْغَدَاةَ وَ اَلْعِشَاءَ اَلْآخِرَةَ فِي جَمَاعَةٍ فَهُوَ فِي ذِمَّةِ اَللَّهِ عَزَّ وَ جَلَّ وَ مَنْ ظَلَمَهُ فَإِنَّمَا يَظْلِمُ اَللَّهَ وَ مَنْ حَقَّرَهُ فَإِنَّمَا يُحَقِّرُ اَللَّهَ عَزَّ وَ جَلَّ.
Imam Jafar ibn Muhammad Al-Sadiq عليه السلام said: "Whoever prays the morning (Fajr) and the evening ('Isha') prayers in congregation is under the protection of Allah سبحانه وتعالى, the Mighty and Majestic. Whoever wrongs him, wrongs Allah سبحانه وتعالى, and whoever belittles him, belittles Allah سبحانه وتعالى, the Mighty and Majestic."
- Ṣaḥīḥ al-Faqīh