´It was narrated that ‘Ali said:` “At every part of the night the Messenger of Allah (ﷺ) prayed Witr, at the beginning and in the middle, and finally his Witr was just before dawn.”
Explanation & Benefits
Maulana Ataullah Sajid
Benefit:
The meaning of Witr ending at true dawn (subh sadiq) is that one performs Witr in the very last part of the night, such that upon finishing, the time for the (Fajr) call to prayer (adhan) has arrived.
That is, Witr is performed before the Fajr adhan.
This is the last time for the Witr prayer.
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 1186