The Book of Leading the Prayer (Al-Imamah)
10/42. Chapter:
Virtue of (prayer in) congregation
Sunan an-Nasai
أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " صَلاَةُ الْجَمَاعَةِ أَفْضَلُ مِنْ صَلاَةِ أَحَدِكُمْ وَحْدَهُ خَمْسًا وَعِشْرِينَ جُزْءًا " .
It was narrated from Abu Hurairah that the Messenger of Allah (ﷺ) said: "Praying in congregation is twenty-five portions better than one of you praying alone."
Reference : Sunan an-Nasa'i 838In-book reference : Book 10, Hadith 62English translation : Vol. 1, Book 10, Hadith 839