The Book of Leading the Prayer (Al-Imamah)
10/42. Chapter:
Virtue of (prayer in) congregation
Sunan an-Nasai
أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ عَمَّارٍ، قَالَ حَدَّثَنِي الْقَاسِمُ بْنُ مُحَمَّدٍ، عَنْ عَائِشَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " صَلاَةُ الْجَمَاعَةِ تَزِيدُ عَلَى صَلاَةِ الْفَذِّ خَمْسًا وَعِشْرِينَ دَرَجَةً " .
It was narrated from that the Prophet (ﷺ) said: "Prayer in congregation is twenty-five levels better than a prayer offered on one's own."
Reference : Sunan an-Nasa'i 839In-book reference : Book 10, Hadith 63English translation : Vol. 1, Book 10, Hadith 840