Narrated AbuSa'id al-Khudri: Prayer in congregation is equivalent to twenty-five prayers (offered alone). If he prays in a jungle, and performs its bowing and prostrations perfectly, it becomes equivalent to fifty prayers (in respect of reward). Abu Dawud said: 'Abd al-Walid b. Ziyad narrated in his version of this tradition: "Prayer said by a single person in a jungle is more excellent by multiplied degrees than prayer said in congregation."
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ عِيسَى، حَدَّثَنَا أَبُو مُعَاوِيَةَ، عَنْ هِلاَلِ بْنِ مَيْمُونٍ، عَنْ عَطَاءِ بْنِ يَزِيدَ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الصَّلاَةُ فِي جَمَاعَةٍ تَعْدِلُ خَمْسًا وَعِشْرِينَ صَلاَةً فَإِذَا صَلاَّهَا فِي فَلاَةٍ فَأَتَمَّ رُكُوعَهَا وَسُجُودَهَا بَلَغَتْ خَمْسِينَ صَلاَةً " . قَالَ أَبُو دَاوُدَ قَالَ عَبْدُ الْوَاحِدِ بْنُ زِيَادٍ فِي الْحَدِيثِ " صَلاَةُ الرَّجُلِ فِي الْفَلاَةِ تُضَاعَفُ عَلَى صَلاَتِهِ فِي الْجَمَاعَةِ " . وَسَاقَ الْحَدِيثَ .
sunnah.com