(45) باب ذِكْرِ الاِخْتِلاَفِ عَلَى سُفْيَانَ الثَّوْرِيِّ فِيهِ
It was narrated from Abu Saeed Al-Khudri that the Prophet said:
"Whoever fasts a day in the cause of Allah, Allah will separate his face from the heat of Hell (a distance of) seventy autumns."
Reference: Sunan an-Nasa'i 2252
In-book reference: Book 22, Hadith 163
English translation: Vol. 3, Book 22, Hadith 2254