Sahih al-Bukhari 998
Book 14: Witr Prayer · Narrated by `Abdullah bin `Umar
Arabic
حَدَّثَنَا مُسَدَّدٌ، قَالَ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ عُبَيْدِ اللَّهِ، حَدَّثَنِي نَافِعٌ، عَنْ عَبْدِ اللَّهِ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " اجْعَلُوا آخِرَ صَلاَتِكُمْ بِاللَّيْلِ وِتْرًا ".
English translation
Narrated `Abdullah bin `Umar:The Prophet (ﷺ) said, "Make witr as your last prayer at night
Reference: Sahih al-Bukhari 998, Book of Witr Prayer. English translation by Dr. Muhammad Muhsin Khan.