The virtue of prayer in congregation, and clarifying the stern warning against staying away from it, and that it is fard kifayah
وَحَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ بْنِ قَعْنَبٍ، حَدَّثَنَا أَفْلَحُ، عَنْ أَبِي بَكْرِ بْنِ مُحَمَّدِ بْنِ عَمْرِو بْنِ حَزْمٍ، عَنْ سَلْمَانَ الأَغَرِّ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " صَلاَةُ الْجَمَاعَةِ تَعْدِلُ خَمْسًا وَعِشْرِينَ مِنْ صَلاَةِ الْفَذِّ " .
Abu Huraira reported Allah's Messenger (ﷺ) as saying: Prayer said in a congregation is equivalent to twenty-five (prayers) as compared with the prayer said by a single person.