Abdullah bin Umar reported,

A man asked the Messenger of Allah ﷺ about the night prayer. The Messenger of Allah replied, "The night prayer is offered in pairs of two. When one of you fears the approach of dawn, let him pray a single rakah, which will make all that he has prayed witr."

Azami 2748

Sahih

عن ابن عمر

أن رجلا سأل رسول الله ﷺ عن صلاة الليل، فقال رسول الله: صلاة الليل مثنى مثنى، فإذا خشي أحدكم الصبح صلى ركعة واحدة توتر له ما قد صلى.

الأعظمي 2748صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Prayer
Chapter
Minor actions do not invalidate the prayer
Section
Night prayer is two rakats at a time, and Witr is one rakat at the end of the night
Numbering
Jami al-Kamil 2748 (2nd edition)
Azami 2748