Sahih Bukhari 1135

Narrated Hudhaifa: Whenever the Prophet got up for Tahajjud prayer he used to clean his mouth (and teeth) with Siwak. ..

Narrated `Abdullah bin `Umar: A man said, O Allah's Apostle! How is the prayer of the night? He said, Two rak`at followed by two rak`at and so on, and when you apprehend the approaching dawn, offer one rak`a as witr. ..

Narrated Ibn `Abbas: The prayer of the Prophet used to be of thirteen rak`at, i.e. of the night prayer. ..

Narrated Masruq: I asked Aisha about the night prayer of Allah's Apostle and she said, It was seven, nine or eleven rak`at besides the two rak`at of the Fajr prayer (i.e. Sunna). ..

Narrated `Aisha: 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. ..

Narrated Anas bin Malik: Sometimes Allah's Apostle 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..