It was narrated from 'Abdullah bin 'Amr that the Messenger of Allah (p) said: 

 أَحَبُّ الصِّيَامِ إِلَى اللَّهِ صِيَامُ دَاوُدَ كَانَ يَصُومُ يَوْمًا وَيُفْطِرُ يَوْمًا

وَأَحَبُّ الصَّلاَةِ إِلَى اللَّهِ صَلاَةُ دَاوُدَ كَانَ يَنَامُ نِصْفَ اللَّيْلِ وَيُصَلِّي ثُلُثَهُ وَيَنَامُ سُدُسَهُ"‏

"The most beloved fast to Allah is the fast of Dawud, for he used to fast one day and not the next. And the most beloved of prayer to Allah is the prayer of Dawud; he used to sleep half of the night, pray one-third of the night and sleep one-sixth of the night." (Sunan Ibn Majah, Saheeh)

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