English translation
2401. It was narrated that 'Abdullāh bin 'Amr said: "The Messenger of Allāh ﷺ said to me: 'O 'Abdullāh bin 'Amr, you fast all the time and you 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, (that is) fasting all of a lifetime.' I said: 'I am able to do more than that.' He said: 'Observe the fast of Dâwûd; he used to fast one day and not the next, and he did not flee if he met (the enemy in battle).'" (Sahîh)
