Sayyiduna Abdullah bin Amr bin al-As (may Allah be pleased with him) says: The Messenger of Allah (peace and blessings be upon him) said to me: I have been informed that you stand in prayer all night and fast every day. I said: Yes, O Messenger of Allah! He (peace and blessings be upon him) said: Fast sometimes and leave fasting sometimes, and stand in prayer at night and also sleep, because your body has a right over you, your wife has a right over you, and your guest has a right over you. Fast three days in a month; that is sufficient for you. But I was strict, so the Prophet (peace and blessings be upon him) was also strict with me. I said: O Messenger of Allah! I have the strength for more than that. He (peace and blessings be upon him) said: Then fast three days every week. But I was strict, so the Prophet (peace and blessings be upon him) was also strict with me, and I said: O Messenger of Allah! I have the strength to fast more than that. He (peace and blessings be upon him) said: Then fast like the Prophet of Allah, Dawud (peace be upon him), and do not exceed that. I said: O Messenger of Allah! How did Dawud (peace be upon him) fast? He (peace and blessings be upon him) said: He would fast one day and leave fasting the next day.