Sahih Muslim 1757
صحيح مسلم#1757Sahihحَدَّثَنَا شَيْبَانُ بْنُ فَرُّوخَ، حَدَّثَنَا عَبْدُ الْوَارِثِ، عَنْ أَبِي التَّيَّاحِ، قَالَ حَدَّثَنِي أَبُو مِجْلَزٍ، عَنِ ابْنِ عُمَرَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الْوِتْرُ رَكْعَةٌ مِنْ آخِرِ اللَّيْلِ " .
Ibn 'Umar reported Allah's Messenger (ﷺ) as saying:Witr is a rak'ah at the end of the prayer
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 6:186