(44) باب ثَوَابِ مَنْ صَامَ يَوْمًا فِي سَبِيلِ اللَّهِ عَزَّ وَجَلَّ وَذِكْرِ الاِخْتِلاَفِ عَلَى سُهَيْلِ بْنِ أَبِي صَالِحٍ فِي الْخَبَرِ فِي ذَلِكَ
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."'
Reference: Sunan an-Nasa'i 2249
In-book reference: Book 22, Hadith 160
English translation: Vol. 3, Book 22, Hadith 2251