Sahih al-Bukhari · Hadith 649

قَالَ شُعَيْبٌ وَحَدَّثَنِي نَافِعٌ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، قَالَ تَفْضُلُهَا بِسَبْعٍ وَعِشْرِينَ دَرَجَةً‏.‏

Narrated `Abdullah bin `Umar:The reward of the congregational prayer is twenty seven times greater (than that of the prayer offered by a person alone)

Narrated by `Abdullah bin `Umar