Sahih Muslim 1749
صحيح مسلم#1749SahihSalim reported on the authority of his father that a person asked the Messenger of Allah (ﷺ) about the night prayer. He said:It consists of pairs of rak'ahs, but if one fears morning is near, he should make it an odd number by praying one rak'ah
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: 6:178