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."

Narrated Nafi`: Ibn `Umar said, "While the Prophet was on the pulpit, a man asked him how to offer the night prayers. He replied, 'Pray two rak`at at a time and then two and then two and so on, and if you are afraid of the dawn (the approach of the time of the Fajr prayer) pray one rak`a and that will be the witr for all the rak`at which you have offered." Ibn `Umar said, "The last rak`at of the night prayer should be odd, for the Prophet ordered it to be so.