question #3 Sahih Muslim 745b, Book 6, Hadith 166 : What is the significance of completing the Witr prayer at dawn?

Masruq reported on the authority of ‘A’isha that she said that the Messenger Of Allah (ﷺ) used to observe the Witr prayer every night, maybe in the early part of night, at midnight and in the latter part, finishing his Witr at dawn.