(31) باب فَضْلِ الصِّيَامِ فِي سَبِيلِ اللَّهِ لِمَنْ يُطِيقُهُ بِلاَ ضَرَرٍ وَلاَ تَفْوِيتِ حَقٍّ
Abu Sa'id al Khudri (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying:
Every servant of Allah who observes fast for a day in the way of Allah, Allah would remove, because of this day, his face farther from the Fire (of Hell) to the extent of seventy years' distance.
Reference: Sahih Muslim 1153 a
In-book reference: Book 13, Hadith 217
USC-MSA web (English) reference(deprecated numbering scheme): Book 6, Hadith 2570