It is narrated from Sayyiduna Ibn Amr (may Allah be pleased with him) that once the Prophet Muhammad (peace and blessings be upon him) came to know that I always fast during the day and stand in prayer at night. So the Prophet (peace and blessings be upon him) sent for me, or perhaps we met by chance, and the Prophet (peace and blessings be upon him) said: "Are you the one about whom I have been told that you say, 'I will stand in prayer every night and fast every day'?" Do not do so, for your eyes have a right over you, your self and your family have a right over you. Therefore, stand in prayer and also sleep, fast and also leave fasting sometimes, and fast only one day in every ten days; you will have the reward of additional nine fasts. I said, 'O Messenger of Allah! I have the strength to do more than that.' The Prophet (peace and blessings be upon him) said: "Then fast like Sayyiduna Dawud (peace be upon him)." I asked, 'O Prophet of Allah! How did Sayyiduna Dawud (peace be upon him) fast?' The Prophet (peace and blessings be upon him) said: "He would fast one day and leave fasting the next day, and he would not flee when facing the enemy." I said, 'O Prophet of Allah! How can I do this?' The Prophet (peace and blessings be upon him) also said twice: "Whoever fasts continuously has not really fasted."