The Prophet ﷺ said, "The witr prayer is performed at night."
حدثنا عبد الصمد حدثنا همام حدثنا يحيى عن أبي نضرة
أن النبي ﷺ قال الوتر بليل
No references are available.
Its isnad is sahih. It is found in Muslim 1/518, no. 752, in the book on travelers, prayer at night in units of two, and in Abu Dawud 1/62, no. 1421, in the book on prayer, on how many units the Witr should be, and in Nasai 3/323, no. 16789, in the book on night prayer, on the Witr.