(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 Abu Saeed Al-Khudri said:
"The Messenger of Allah said: 'Whoever fasts one day in the cause of Allah, Allah will separate between his face and the fire by (a distance of) seventy autumns in return for that day."'
Reference: Sunan an-Nasa'i 2245
In-book reference: Book 22, Hadith 156
English translation: Vol. 3, Book 22, Hadith 2247