That he asked `Aisha "How was the prayer of Allah's Messenger (ﷺ) in the month of Ramadan?" She replied, "He used not to pray more than eleven rak`at whether in Ramadan or in any other month. He used to offer four rak`at, let alone their beauty and length, and then four rak`at, let alone their beauty and length. Afterwards he would offer three rak`at. I said, 'O Allah's Messenger (ﷺ)! Do you go to bed before offering the witr prayer?' He said, 'My eyes sleep, but my heart does not sleep."'

Sahih al-Bukhari Book 61, Hadith 78