Muwatta Malik #264

Yahya related to me from Malik from Said ibn Abi Said al-Maqburi from Abu Salama ibn Abd ar-Rahman ibn Awf that he asked A'isha, the wife of the Prophet, may Allah bless him and grant him peace, what the prayer of the Messenger of Allah, may Allah bless him and grant him peace, was like during Ramadan. She said, "The Messenger of Allah, may Allah bless him and grant him peace, did not go above eleven rakas in Ramadan or at any other time. He prayed four - do not ask me about their beauty or length. Then he prayed another four - do not ask me about their beauty and length. Then he prayed three." A'isha continued, "I said, 'Messenger of Allah, are you sleeping before you do the witr?' He said, A'isha, my eyes sleep but my heart does not sleep.' "