Sometimes Allah's Messenger (ﷺ) would not fast (for so many days) that we thought that he would not fast that month and he sometimes used to fast (for so many days) that we thought he would not leave fasting throughout that month and (as regards his prayer and sleep at night), if you wanted to see him praying at night, you could see him praying and if you wanted to see him sleeping, you could see him sleeping.
Sahih al-Bukhari Book 19, Hadith 22
← Previous Hadith The Prophet (p.b.u.h) used to offer thirteen rak`at of the night prayer and that included the witr and two rak`at (Sunna) of the Fajr prayer.

Sahih al-Bukhari Book 19, Hadith 21 Next Hadith → Allah's Messenger (ﷺ) said, "Satan puts three knots at the back of the head of any of you if he is asleep. On every knot he reads and exhales the following words, 'The night is long, so stay asleep.' When one wakes up and remembers Allah, one knot is undone; and when one performs ablution, the second knot is undone, and when one prays the third knot is undone and one gets up energetic with a good heart in the morning; otherwise one gets up lazy and with a mischievous heart."

Sahih al-Bukhari Book 19, Hadith 23