"He used to pray 'Isha, then he would recite tasbih, then after that he would pray whatever Allah (SWT) willed (he should pray) of night prayer. Then he would go and sleep for as long as he had prayed. Then he would get up from sleep and pray for as long as he had slept, and this last prayer of his would continue until dawn."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ عَبْدِ اللَّهِ بْنِ عُبَيْدِ اللَّهِ بْنِ أَبِي مُلَيْكَةَ، عَنْ يَعْلَى بْنِ مَمْلَكٍ، أَنَّهُ سَأَلَ أُمَّ سَلَمَةَ زَوْجَ النَّبِيِّ صلى الله عليه وسلم عَنْ قِرَاءَةِ رَسُولِ اللَّهِ صلى الله عليه وسلم وَعَنْ صَلاَتِهِ فَقَالَتْ مَا لَكُمْ وَصَلاَتَهُ كَانَ يُصَلِّي ثُمَّ يَنَامُ قَدْرَ مَا صَلَّى ثُمَّ يُصَلِّي قَدْرَ مَا نَامَ ثُمَّ يَنَامُ قَدْرَ مَا صَلَّى حَتَّى يُصْبِحَ . ثُمَّ نَعَتَتْ لَهُ قِرَاءَتَهُ فَإِذَا هِيَ تَنْعَتُ قِرَاءَةً مُفَسَّرَةً حَرْفًا حَرْفًا .
"What do you want to know about his prayer (I.e., you can never match it)? He used to pray, then sleep for as long as he had prayed, then he would pray as long as he had slept, then he would sleep as long as he had prayed, until dawn came." Then she described to him his recitation, and she described a clear recitation in which every letter was distinct.
"The Messenger of Allah (ﷺ) said: 'The most beloved of fasting to Allah is the fasting of Dawud, peace be upon him. He used to fast one day and not the next. And the most beloved of prayer to Allah (SWT) is the prayer of Dawud. He used to sleep half the night, spend one-third of the night in prayer and sleep for one-sixth of it.'"
The Messenger of Allah (ﷺ) said: "On the night on which I was taken on the Night Journey (Al-Isra') I came to Musa, peace be upon him, at the red dune, and he was standing, praying in his grave."
"The Messenger of Allah (ﷺ) said: 'On the night on which I was taken on the Night Journey, I passed by Musa, peace be upon him, and he was praying in his grave.'"
أَخْبَرَنَا يَحْيَى بْنُ حَبِيبِ بْنِ عَرَبِيٍّ، وَإِسْمَاعِيلُ بْنُ مَسْعُودٍ، قَالاَ حَدَّثَنَا مُعْتَمِرٌ، قَالَ سَمِعْتُ أَبِي قَالَ، سَمِعْتُ أَنَسًا، يَقُولُ أَخْبَرَنِي بَعْضُ، أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم أَنَّ النَّبِيَّ صلى الله عليه وسلم لَيْلَةَ أُسْرِيَ بِهِ مَرَّ عَلَى مُوسَى عَلَيْهِ السَّلاَمُ وَهُوَ يُصَلِّي فِي قَبْرِهِ .
"I heard my father say: I heard Anas say: 'One of the companions of the Prophet (ﷺ) told me that on the Night Journey, the Prophet (ﷺ) passed by Musa, peace be upon him, and he was praying in his grave.'"