Sahih Muslim 1767
صحيح مسلم#1767SahihJabir 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 is witnessed*, and that is better. *: meaning, "by angels" (Sharh an-Nawawi)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 6:196