Muhammad bin Abi Harmala محمد بن أبي حرملة · The Book of Fasting

"The Messenger of Allah said: 'There has come to you Ramadan, a blessed month, which Allah, the Mighty and Sublime, has enjoined you to fast. In it the gates of heavens are opened and the gates of Hell are closed, and every devil is chained up. In it Allah has a night which is better than a thousand months; whoever is deprived of its goodness is indeed deprived."'

"The Messenger of Allah said to me: 'O 'Abdullah bin 'Amr, you fast all the time and you do stand (in prayer) at night, but if you do that your eyes will become sunken and you will become exhausted. There is no fast for one who fasts every day of his life. Fasting a lifetime means fasting three days each month,