One who fasts a single day is distanced from Hellfires at a distance of seventy years

I heard the Prophet ﷺ saying, "Indeed, anyone who fasts for one day for Allah's Pleasure, Allah will keep his face away from the (Hell) fire for (a distance covered by a journey of) seventy years."  

سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ: «مَنْ صَامَ يَوْمًا فِي سَبِيلِ اللَّهِ بَعَّدَ اللَّهُ وَجْهَهُ عَنِ النَّارِ سَبْعِينَ خَرِيفًا۔»