Volume 2, Book 16, Number 105:
Narrated Ibn Umar:
Once a person asked Allah’s Apostle about the night prayer. Allah’s Apostle replied, “The night prayer is offered as two Rakat followed by two Rakat and so on and if anyone is afraid of the approaching dawn (Fajr prayer) he should pray one Raka and this will be a Witr for all the Rakat which he has prayed before.” Nafi’ told that ‘Abdullah bin ‘Umar used to say Taslim between (the first) two Rakat and (the third) odd one in the Witr prayer, when he wanted to attend to a certain matter (during that interval between the Rakat).
Volume 2, Book 16, Number 106:
Narrated Ibn ‘Abbas:
Once I passed the night in the house of Maimuna (his aunt). I slept across the bed while Allah’s Apostle and his wife slept length-wise. The Prophet slept till midnight or nearly so and woke up rubbing his face and recited ten verses from Surat “Aal-Imran.” Allah’s Apostle went towards a leather skin and performed ablution in the most perfect way and then stood for the prayer. I did the same and stood beside him. The Prophet put his right hand on my head, twisted my ear and then prayed two Rakat five times and then ended his prayer with Witr. He laid down till the Muadh-dhin came then he stood up and offered two Rakat (Sunna of Fajr prayer) and then went out and offered the Fajr prayer.
(See Hadith No. 183, Vol. 1)
Volume 2, Book 16, Number 107:
Narrated ‘Abdullah bin ‘Umar :
The Prophet said, “Night prayer is offered as two Rakat followed by two Rakat and so on, and if you want to finish it, pray only one Raka which will be Witr for all the previous Rakat.” Al-Qasim said, “Since we attained the age of puberty we have seen some people offering a three-Rakat prayer as Witr and all that is permissible. I hope there will be no harm in it.”
Volume 2, Book 16, Number 108:
Allah’s Apostle used to pray eleven Rakat at night and that was his night prayer and each of his prostrations lasted for a period enough for one of you to recite fifty verses before Allah’s Apostle raised his head. He also used to pray two Rakat (Sunna) before the (compulsory) Fajr prayer and then lie down on his right side till the Muadh-dhin came to him for the prayer.
Volume 2, Book 16, Number 109:
Narrated Anas bin Sirin:
I asked Ibn ‘Umar, “What is your opinion about the two Rakat before the Fajr (compulsory) prayer, as to prolonging the recitation in them?” He said, “The Prophet (p.b.u.h) used to pray at night two Rakat followed by two and so on, and end the prayer by one Raka Witr. He used to offer two Rakat before the Fajr prayer immediately after the Adhan.” (Hammad, the sub-narrator said, “That meant (that he prayed) quickly.)”