مُوَطَّأُ مَالِكٍ
Muwatta Malik 288
Prayer in Congregation
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ صَلاَةُ الْجَمَاعَةِ تَفْضُلُ صَلاَةَ الْفَذِّ بِسَبْعٍ وَعِشْرِينَ دَرَجَةً .
Yahya related to me from Malik from Nafi from Abdullah ibn Umar that the Messenger of Allah, (ﷺ), said, "Prayer in congregation is better than the prayer of a man by himself by twenty-seven degrees."
Arabic/English book reference: Book 8, Hadith 1