The Messenger of Allah ﷺ entered my room and said, "Have I not been told that you stand in prayer all night and fast all day?"I replied, "Yes."He said, "Do not do so. Sleep and rise, fast and break your fast. Your eye has a right over you, your body has a right over you, your wife has a right over you, your guest has a right over you, and your friend has a right over you. You may live a long life, and it is enough for you to fast three days of each month, for that is equivalent to fasting the whole year, since a good deed is rewarded tenfold."I said, "I find I have the strength for more." So I pressed, and he pressed upon me. He said, "Then fast three days each week."I said, "I can manage more than that." So I pressed, and he pressed upon me. He said, "Then fast as the Prophet of Allah Dawud used to fast."I asked, "And what was the fast of Dawud?"He answered, "Half of all time."
أخبرنا يحيى بن درست قال حدثنا أبو إسمعيل قال حدثنا يحيى بن أبي كثير أن أبا سلمة حدثه أن
دخل رسول الله ﷺ حجرتي فقال ألم أخبر أنك تقوم الليل وتصوم النهار قال بلى قال فلا تفعلن نم وقم وصم وأفطر فإن لعينك عليك حقا وإن لجسدك عليك حقا وإن لزوجتك عليك حقا وإن لضيفك عليك حقا وإن لصديقك عليك حقا وإنه عسى أن يطول بك عمر وإنه حسبك أن تصوم من كل شهر ثلاثا فذلك صيام الدهر كله والحسنة بعشر أمثالها قلت إني أجد قوة فشددت فشدد علي قال صم من كل جمعة ثلاثة أيام قلت إني أطيق أكثر من ذلك فشددت فشدد علي قال صم صوم نبي الله داود عليه السلام قلت وما كان صوم داود قال نصف الدهر
Bukhari related it in the Book of Fasting, chapter "The Right of the Guest Regarding Fasting," no. 1974, and Muslim in the Book of Fasting, chapter "The Prohibition of Fasting Every Day for One Who Would Be Harmed by It," etc., no. 1159, from the hadith of Yahya, through him. It is also in Al-Kubra, no. 2699.Abu Ismail is Al-Qannad.