Hadith 5:96
Abu Sa‘id al-Khudri reported God’s messenger as saying, “If anyone fasts for a day while engaged in jihad , God will remove him* seventy years’ distance from hell.” *Literally, ‘his face’. (Bukhari and Muslim.)
وَعَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ صَامَ يَوْمًا فِي سَبِيلِ اللَّهِ بَعَّدَ اللَّهُ وَجْهَهُ عَنِ النَّارِ سَبْعِينَ خَرِيفًا»
Original Reference: Mishkat al-Masabih 2053