The prayer in the Mosque is twenty-seven times more excellent than prayer by oneself. (Shaikh Ibn ‘Uthaimeen)

Shaikh Ibn ‘Uthaimeen (rahimahullāh) said: “And guard your prayers by praying them in the Mosques, for the prayer in the Mosque is twenty-seven times more excellent than prayer by oneself – and the greater the congregation, the more beloved it is to Allāh (the Mighty and Majestic) and the more steps a person takes walking to the Mosque the greater the reward. Indeed the one who performs ablution (wudū) and perfects his ablution in his home, then leaves out to go to the mosque, wishing for nothing other than the prayer, then he does not place a step, except that with every step Allāh raises him in rank and wipes away a sin.”

‘Abdullāh bin ʿUmar (Allah be pleased with him) narrated that Allāh’s Messenger (salallāhu ‘alaihi wasallam) said:

صَلَاةُ الْجَمَاعَةِ تَفْضُلُ صَلَاةَ الْفَذِّ بِسَبْعٍ وَعِشْرِينَ دَرَجَةً

“The congregational prayer is twenty-seven times more virtuous than the prayer of a person praying alone.”

Reported by al-Bukhārī, no. 645.

Taken from volume II of:
Ad-Diyā’ al-Lāmiʿ min al-Khutub al-Jawāmiʿ.