The Prophet ﷺ said, "Make the last of your prayers at night the witr."
حدثنا أحمد بن حنبل حدثنا يحيى عن عبيد الله حدثني نافع
عن النبي ﷺ قال اجعلوا آخر صلاتكم بالليل وترا
Bukhari narrated it in Witr, chapter, "Let him make the last of his prayer Witr," no. 998, and Muslim in the prayer of travelers, chapter, "the night prayer is two by two and Witr is one rakat at the end of the night," no. 751, from the hadith of Yahya Qattan through this same chain. It is also found in Musnad Ahmad, 2/20.