Jabir reported Allah's Messenger (ﷺ) as saying: If anyone is afraid that he may not get up in the latter part of the night, he should observe Witr in the first part of it; and if anyone is eager to get up in the last part of it, he should observe Witr at the end of the night, for prayer at the end of the night is witnessed (by the angels) and that is preferable.
Hadith Referenceصحيح مسلم / كتاب صلاة المسافرين وقصرها / 755
Jabir reported Allah's Messenger (ﷺ) as saying: He who amongst you is afraid that he may not be able to get up at the end of the night should observe Witr (in the first part) and then sleep, and he who is confident of getting up and praying at night (i. e. Tahajjud prayer) should observe it at the end of it, for the recitation at the end of the night to visited (by angels), and that is excellent.
Hadith Referenceصحيح مسلم / كتاب صلاة المسافرين وقصرها / 755
´It was narrated from Jabir that the Messenger of Allah (ﷺ) said:` “Whoever among you fears that he will not wake up at the end of the night, let him pray Witr at the beginning of the night, then go to sleep. Whoever hopes that he will wake up at the end of the night, let him pray Witr at the end of the night, for recitation (of the Qur’an) at the end of the night is attended (by the angels), and that is better.”
Maulana Ataullah Sajid
Benefits and Issues:
➊ It is more virtuous to perform the witr prayer in the last part of the night.
➋ At that time, it is also more virtuous to perform some voluntary (nafl) prayers before witr.
➌ The angels have great love for the recitation of the Noble Qur'an. Therefore, they especially gather to listen to the recitation of a believer.
➍ This gathering of the angels takes place in the last part of the night.
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 1187