عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ: ((لَا يَصُومُ عَبْدٌ يَوْمًا فِي سَبِيلِ اللَّهِ إِلَّا بَاعَدَ اللَّهُ بِذَلِكَ الْيَوْمِ النَّارَ عَنْ وَجْهِهِ سَبْعِينَ خَرِيفًا))
Narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him), the Messenger of Allah (peace and blessings be upon him) said: Whoever fasts for one day in the way of Allah, Allah Almighty will, because of that one day's fast, distance him from Hell by a distance of seventy years.