Narrated Anas bin Seereen: I asked Ibn `Umar, "What is your opinion about the two rak`at 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 rak`at followed by two and so on, and end the prayer by one rak`a witr. He used to offer two rak`at before the Fajr prayer immediately after the Adhan." (Hammad, the sub-narrator said, "That meant (that he prayed) quickly.)"

Narrated `Aisha: Allah's Apostle offered witr prayer at different nights at various hours extending (from the `Isha' prayer) up to the last hour of the night.