Tahajjud
The time for Tahajjud Salaat commences from after Isha Salaat and ends with Subh Saadiq.
According to the Hadith, Rasulullah (Sallallahu alaihi wasallam) would commence Tahajjud Salaat during the early period of the night, during the middle of the night as well as during the later period of the night.
The later it is, the better. Greater mercies and blessings descend during the later part of the night. The last sixth of the night has greater significance. It is the best part of the night.
It is not incumbent to first sleep then rise for Tahajjud, although this is the best course.
Those who find it too difficult to rise in the later part of the night for Tahajjud Salaat should perform Tahajjud before going to bed.
(The Majlis Archives)