It was narrated that 'Abdullah bin 'Amr said: "The Messenger of Allah said: "The best of fasting is the fast of Dawud, peace be upon him. He used to fast for one day and break his fast for one day."' 'Ata said: "someone who heard him told me that Ibn 'Umar (said) that the Prophet said: 'Whoever fasts every day of his life, then he has not fasted."