"Whoever prays during the night, let him make the last of his prayers at night witr, because the Messenger of Allah (ﷺ) used to enjoin that."
Sunan an-Nasa'i Book 20, Hadith 85
← Previous Hadith "The Messenger of Allah (ﷺ) prayed witr at the beginning (of the night) and at the end, and in the middle. And toward the end of his life, he settled on performing witr at the end of the night."

Sunan an-Nasa'i Book 20, Hadith 84 Next Hadith → "The Messenger of Allah (ﷺ) was asked about witr and he said: 'Pray witr before dawn (Subh).'"

Sunan an-Nasa'i Book 20, Hadith 86