Riyad as-Salihin: The Book of Virtues – Hadith No. 459 — Jabir (May Allah be pleased with him)reported: The Messenger of Allah (ﷺ) said… (Hadith No. 459)

Jabir (May Allah be pleased with him)reported: The Messenger of Allah (ﷺ) said, "He who apprehends that he may not get up in the later part of the night, should observe the Witr prayer in the first part of it; and he who is certain to get up in the last part of it, he should observe Witr at the end of the night, because Salat at the end of the night is attended (by the angels), and that is better.".

Explanation:

Reference: Riyad as-Salihin, The Book of Virtues, Hadith No. 459