Anas bin Sirin reported,

I asked Ibn Umar, "Tell me about the two units of prayer before the dawn prayer. Should I prolong the recitation in them?"He replied, "The Messenger of Allah ﷺ used to pray during the night in pairs, and he would conclude with a single unit as witr."I said, "That is not what I am asking you about."He said, "You are dense! Will you not let me lay out the hadith for you? The Messenger of Allah ﷺ used to pray during the night in pairs, conclude with a single unit as witr, and pray two short units before the dawn prayer, as though the call to prayer were already in his ears."In another narration, he said, "Easy, easy! You are dense indeed."In another narration, the Messenger of Allah said, "The night prayer is in pairs. When you fear that dawn is about to overtake you, conclude with a single unit as witr."Ibn Umar was asked, "What is meant by 'in pairs'?"He replied, "That you give the closing salutation after every two units."

Azami 2749

Sahih

عن أنس بن سيرين قال

سألت ابن عمر، قلت: أرأيت الركعتين قبل صلاة الغداة أ أطيل فيهما القراءة؟ قال: كان رسول الله ﷺ يصلي من الليل مثنى مثنى، ويوتر بركعة. قال: قلت: إني لست عن هذا أسألك. قال: إنك لضخم. ألا تدعني استقرى لك الحديث؟ كان رسول الله ﷺ يصلي من الليل مثنى مثنى، ويوتر بركعة، ويصلي ركعتين قبل الغداة. كأن الأذان بأذنيه. وفي رواية: فقال: به به إنك لضخم. وفي رواية: قال رسول الله: صلاة الليل مثنى مثنى. فإذا رأيت أن الصبح يدركك فأوتر بواحدة، فقيل لابن عمر: ما مثنى مثنى؟ قال: أن يسلم في كل ركعتين.

الأعظمي 2749صحيح
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 2749 (2nd edition)
Azami 2749