(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 from Abu Sa`eed that the Prophet (ﷺ) said:
"Whoever fasts one day in the cause of Allah, the Mighty and Sublime, Allah will separate his face from the fire by (a distance of) seventy years."
Reference: Sunan an-Nasa'i 2247
In-book reference: Book 22, Hadith 158
English translation: Vol. 3, Book 22, Hadith 2249