Yahya bin Abu Kathir reported,

With this chain of narration, with the following addition after his words "three days of every month", he said, "For every good deed you receive a tenfold reward, so that amounts to fasting the entire year."In this version of the hadith he said, "I asked, 'And what is the fast of the Prophet of Allah Dawud?' He replied, 'Half of all time.'"This narration does not mention anything about the recitation of the Quran, nor does it include the words, "And your visitor has a right over you." Instead it says, "And your child has a right over you."

Muslim 2731

Sahih

و حدثنيه زهير بن حرب حدثنا روح بن عبادة حدثنا حسين المعلم

عن يحيى بن أبي كثير

بهذا الإسناد وزاد فيه بعد قوله من كل شهر ثلاثة أيام فإن لك بكل حسنة عشر أمثالها فذلك الدهر كله وقال في الحديث قلت وما صوم نبي الله داود قال نصف الدهر ولم يذكر في الحديث من قراءة القرآن شيئا ولم يقل وإن لزورك عليك حقا ولكن قال وإن لولدك عليك حقا

مسلم 2731صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Fasting
Chapter
Prohibition of perpetual fasting for one who is harmed by it or neglects a right because of it or does not break fast on the two Eids and Tashriq, and explanation of the virtue of fasting one day and breaking fast one day
Numbering
Darussalam 2731
Muslim 2731