حَدَّثَنَا إِسْحَاقُ، أَخْبَرَنَا هَارُونُ بْنُ إِسْمَاعِيلَ، حَدَّثَنَا عَلِيٌّ، حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنِي أَبُو سَلَمَةَ، قَالَ حَدَّثَنِي عَبْدُ اللَّهِ بْنُ عَمْرِو بْنِ الْعَاصِ ـ رضى الله عنهما ـ قَالَ دَخَلَ عَلَىَّ رَسُولُ اللَّهِ صلى الله عليه وسلم فَذَكَرَ الْحَدِيثَ يَعْنِي ‏"‏ إِنَّ لِزَوْرِكَ عَلَيْكَ حَقًّا، وَإِنَّ لِزَوْجِكَ عَلَيْكَ حَقًّا ‏"‏‏.‏ فَقُلْتُ وَمَا صَوْمُ دَاوُدَ قَالَ ‏"‏ نِصْفُ الدَّهْرِ ‏"‏‏.‏
Translation
Narrated `Abdullah bin `Amr bin Al-`As

"Once Allah's Messenger (ﷺ) came to me," and then he narrated the whole narration, i.e. your guest has a right on you, and your wife has a right on you. I then asked about the fasting of David. The Prophet (ﷺ) replied, "Half of the year," (i.e. he used to fast on every alternate day).