The Messenger of Allah ﷺ said, "Whoever fasts a single day for the sake of Allah, Allah will distance his face from the Fire by a span of seventy autumns."
حدثنا أنس بن عياض عن سهيل بن أبي صالح عن أبيه
أن رسول الله ﷺ قال من صام يوما في سبيل الله زحزح الله وجهه عن النار بذلك سبعين خريفا
Its isnad is sahih. Nasai (1:313) narrated it from Yunus bin Abdul-Ala, from Anas bin Iyad, with this same isnad. Ibn Majah (1718) narrated it from Hisham bin Ammar, from Anas bin Iyad, from Abdullah bin Abdul-Aziz Laythi, from Maqburi, from Abu Hurairah. Tirmidhi (vol. 3, p. 2) narrated it through the route of Ibn Lahia, from Abu Aswad Muhammad bin Abdul-Rahman bin Nawfal, from Urwa and Sulayman bin Yasar, from Abu Hurairah, and he said, "This is a gharib hadith from this angle." Munziri mentioned it in Targheeb wa Tarheeb (2:62) and attributed it to Tirmidhi, Nasai, and Ibn Majah.It will come again at 8675 through the narration of Abdul-Rahman bin Zayd, from his father, from Abu Salih Samman, from Abu Hurairah. The hadith is also confirmed through the hadith of Abu Saeed Khudri, which will come in the Musnad at 11428 and 11426, and it was narrated by the two Shaykhs and others, as noted in Targheeb (2:62).