Muhammad bin Kathir bin Abi 'Ata' محمد بن كثير بن أبي عطاء الثقفي · The Book of Fasting

"The Messenger of Allah: 'There is no worshipper who fasts a day in the cause of Allah, but Allah, the most high, will separate (a distance of) seventy autumns between his face and the fire in return for that day."'