(20) باب صَلاَةُ اللَّيْلِ مَثْنَى مَثْنَى وَالْوِتْرُ رَكْعَةٌ مِنْ آخِرِ اللَّيْلِ
Ibn 'Umar reported Allah's Messenger (ﷺ) as saying:
Make Witr the end of your night prayer. (ID)
Reference (ID): Sahih Muslim 751 b (ID)
In-book reference (ID): Book 6, Hadith 184 (ID)
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1639 (ID)