Abu Huraira said, "I heard Messenger of Allah ﷺ saying, 'The reward of a prayer in congregation is twenty five times greater than that of a prayer offered by a person alone. The angels of the night and the angels of the day gather at the time of Fajr prayer.' " Abu Huraira then added, "Recite the Holy Book if you wish, for "Indeed, the recitation of the Qur'an in the early dawn (Fajr prayer) is ever witnessed." (17:78).  

سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ تَفْضُلُ صَلاَةُ الْجَمِيعِ صَلاَةَ أَحَدِكُمْ وَحْدَهُ بِخَمْسٍ وَعِشْرِينَ جُزْءًا وَتَجْتَمِعُ مَلاَئِكَةُ اللَّيْلِ وَمَلاَئِكَةُ النَّهَارِ فِي صَلاَةِ الْفَجْرِ ثُمَّ يَقُولُ أَبُو هُرَيْرَةَ فَاقْرَءُوا إِنْ شِئْتُمْ {إِنَّ قُرْآنَ الْفَجْرِ كَانَ مَشْهُودًا}  

The reward of the congregational prayer is twenty seven times greater (than that of the prayer offered by a person alone).  

تَفْضُلُهَا بِسَبْعٍ وَعِشْرِينَ دَرَجَةً  

I heard Um Ad-Darda' saying, "Abu Ad-Darda' entered the house in an angry mood. I said to him. 'What makes you angry?' He replied, 'By Allah! I do not find the followers of Muhammad doing those good things (which they used to do before) except the offering of congregational prayer." (This happened in the last days of Abu Ad-Darda' during the rule of ʿUthman) .  

سَمِعْتُ أُمَّ الدَّرْدَاءِ تَقُولُ دَخَلَ عَلَىَّ أَبُو الدَّرْدَاءِ وَهْوَ مُغْضَبٌ فَقُلْتُ مَا أَغْضَبَكَ فَقَالَ وَاللَّهِ مَا أَعْرِفُ مِنْ أُمَّةِ مُحَمَّدٍ ﷺ شَيْئًا إِلاَّ أَنَّهُمْ يُصَلُّونَ جَمِيعًا  

The Prophet ﷺ said, "The people who get tremendous reward for the prayer are those who are farthest away (from the mosque) and then those who are next farthest and so on. Similarly one who waits to pray with the Imam has greater reward than one who prays and goes to bed. "  

قَالَ النَّبِيُّ ﷺ أَعْظَمُ النَّاسِ أَجْرًا فِي الصَّلاَةِ أَبْعَدُهُمْ فَأَبْعَدُهُمْ مَمْشًى وَالَّذِي يَنْتَظِرُ الصَّلاَةَ حَتَّى يُصَلِّيَهَا مَعَ الإِمَامِ أَعْظَمُ أَجْرًا مِنَ الَّذِي يُصَلِّي ثُمَّ يَنَامُ