The Book of Fasting
13/31. Chapter:
The Virtue of Fasting for in the cause of Allah, for those who are able to without suffering any harm or neglecting other duties
Sahih Muslim
وَحَدَّثَنَا مُحَمَّدُ بْنُ رُمْحِ بْنِ الْمُهَاجِرِ، أَخْبَرَنِي اللَّيْثُ، عَنِ ابْنِ الْهَادِ، عَنْ سُهَيْلِ بْنِ، أَبِي صَالِحٍ عَنِ النُّعْمَانِ بْنِ أَبِي عَيَّاشٍ، عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ، - رضى الله عنه - قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَا مِنْ عَبْدٍ يَصُومُ يَوْمًا فِي سَبِيلِ اللَّهِ إِلاَّ بَاعَدَ اللَّهُ بِذَلِكَ الْيَوْمِ وَجْهَهُ عَنِ النَّارِ سَبْعِينَ خَرِيفًا " .
Abu Sa'id al Khudri (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying: Every servant of Allah who observes fast for a day in the way of Allah, Allah would remove, because of this day, his face farther from the Fire (of Hell) to the extent of seventy years' distance.
Reference : Sahih Muslim 1153aIn-book reference : Book 13, Hadith 217USC-MSA web (English) reference : Book 6, Hadith 2570