The Messenger of Allah ﷺ said, "The night prayer is to be performed two by two. When you sense that dawn is approaching, conclude with a single witr."Someone asked Ibn Umar, "What does 'two by two' mean?"He answered, "You give the salam after every two units."
حدثنا محمد بن جعفر حدثنا شعبة سمعت عقبة بن حريث سمعت
عن رسول الله ﷺ قال صلاة الليل مثنى مثنى فإذا رأيت أن الصبح يدركك فأوتر بواحدة قال فقيل لابن عمر ما مثنى مثنى قال تسلم في كل ركعتين
Its isnad is sahih. It is an abridgment of 5470, but Ibn Umar's tafsir of "two by two" was not mentioned in any of the previous narrations. This supports the soundness of the earlier hadith, 5461, regarding separating Witr from the pairs with a taslimah, and the phrase "two by two" points to this, though Ibn Umar's own explanation of it is clearer and more explicit, removing the possibility of forced interpretations by those who strain to interpret otherwise.His statement, "the hadith from the Messenger of Allah" appears in a copy in the margin of K and M as "that" instead of "from."