He reported God’s Messenger as saying, “The witr* is a rak'a at the end of the night.” * Literally ‘single’, or ‘odd’, used of an odd number of rak'as prayed at some time during the night. Muslim transmitted it.
Hadith Referenceمشكوة المصابيح / كتاب الصلاة / 1255
Hadith Gradingالألبانی:صَحِيح | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه مسلم (752/153)»