I heard the Prophet ﷺ being asked about the night prayer. He said, "Two by two, and when you fear the approach of dawn, conclude with a single rakah as witr."
حدثنا سفيان عن ابن أبي لبيد عن أبي سلمة
سمعت النبي ﷺ سئل عن صلاة الليل فقال مثنى مثنى فإذا خفت الصبح فأوتر بواحدة
Its isnad is sahih. Ibn Abu Labid is Abdullah. Abu Salama is the son of Abdul-Rahman bin Awf. This hadith is a repeat of 4559.