أَخْبَرَنَا الْحَسَنُ بْنُ قَزَعَةَ، عَنْ حُمَيْدِ بْنِ الأَسْوَدِ، قَالَ حَدَّثَنَا سُهَيْلٌ، عَنِ النُّعْمَانِ بْنِ أَبِي عَيَّاشٍ، قَالَ سَمِعْتُ أَبَا سَعِيدٍ الْخُدْرِيَّ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ صَامَ يَوْمًا فِي سَبِيلِ اللَّهِ عَزَّ وَجَلَّ بَاعَدَهُ اللَّهُ عَنِ النَّارِ سَبْعِينَ خَرِيفًا " .
It was narrated that An-Numan bin Abi 'Ayyash said: "I heard Abu Saeed Al-Khudri say: 'The Messenger of Allah said: Whoever fasts one day in the cause of Allah will separate his face from the fire by (a distance of) seventy autumns."' Translation Not Available
Book Ref: Sunan An Nisai Book 22 Hadith 2249
Web Ref: Sunan An Nisai Vol 3 Book 22 Hadith 2251