The Prophet ﷺ was asked about the night prayer. He replied, "It is to be performed two units at a time, and when you fear the approach of dawn, pray a single unit to make it odd."
حدثنا عبد الرزاق أخبرنا سفيان عن حبيب بن أبي ثابت عن طاوس
سئل النبي ﷺ عن صلاة الليل فقال مثنى مثنى فإذا خشيت الصبح فواحدة
Its isnad is sahih, and it is an abridgment of 5793. Sufyan is Thawri.