The Messenger of Allah ﷺ said, "The most beloved fasting to Allah is the fasting of Dawud, and the most beloved prayer to Allah is the prayer of Dawud. He would sleep half the night, stand in prayer for a third of it, and sleep for a sixth of it. He would fast one day and break his fast the next."
حدثنا سفيان سمعت عمرا أخبرني عمرو بن أوس سمعه من
قال رسول الله ﷺ أحب الصيام إلى الله صيام داود وأحب الصلاة إلى الله صلاة داود كان ينام نصفه ويقوم ثلثه وينام سدسه وكان يصوم يوما ويفطر يوما
Its chain of transmission is sahih. Sufyan is Ibn Uyayna. "I heard Amr" refers to Amr bin Dinar, Abu Muhammad al-Makki, a trustworthy leading successor. His trustworthiness was already established at 1391, and here we add the statement of Ibn Uyayna, "He was trustworthy, trustworthy, trustworthy, and a hadith I hear from Amr is dearer to me than twenty hadiths from anyone else." Bukhari gave his biography in al-Saghir p. 85, and Ibn Abu Hatim in al-Jarh wal-Tadil 3/1/231.Amr bin Aws al-Thaqafi al-Taifi is a trustworthy successor. His trustworthiness was already established at 1705, and here we add that Ibn Abu Hatim gave his biography in al-Jarh wal-Tadil 3/1/220, and it is reported from Ibn Labiba that he said, "I asked Abu Hurairah about something, and he said, 'Where are you from?' I said, 'From Thaqif.' He said, 'You ask me when Amr bin Aws is among you?'"This hadith is, in reality, part of the long hadith that has already passed at 6477, where we pointed out its numbers in the Musnad and its citations from the reference collections. As for this particular route specifically, it was narrated by Bukhari 3:13-14 and 6:327, Muslim 1:320, Abu Dawud 2448 (2:303 of Awn al-Mabud), Nasai 1:242, Ibn Majah 1:269, and Darimi 2:20, all of them through the route of Sufyan bin Uyayna, with this same chain of transmission. Abu Dawud's narration was related by him from Ahmad bin Hanbal, Muhammad bin Isa, and Musaddad, all three of them from Sufyan. It will also come again at 6921 from the narration of Ibn Jurayj from Amr bin Dinar with similar wording.A useful note, in Darimi's narration it occurs, "He would pray half, sleep a third, and glorify Allah a sixth." Darimi said this last wording is a mistake or an error, rather it means that he would sleep half the night, pray a third of it, and glorify Allah a sixth of it. But Darimi himself also erred here, for the correct version is "and sleep a sixth of it," as it appears in the Musnad's narration here and in all the other narrations we have pointed to.