Sunan an-Nasa'i #1681 · The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day

Sunan an-Nasa'iIt was narrated that Aishah said
Sunan an-Nasa'i · Book 20 · The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day
Sunan an-Nasa'i · كتاب 20 · كتاب قيام الليل وتطوع النهار
"The Messenger of Allah (ﷺ) prayed witr at the beginning (of the night) and at the end, and in the middle. And toward the end of his life, he settled on performing witr at the end of the night
أَخْبَرَنَا إِسْحَاقُ بْنُ مَنْصُورٍ، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ، عَنْ سُفْيَانَ، عَنْ أَبِي حَصِينٍ، عَنْ يَحْيَى بْنِ وَثَّابٍ، عَنْ مَسْرُوقٍ، عَنْ عَائِشَةَ، قَالَتْ أَوْتَرَ رَسُولُ اللَّهِ صلى الله عليه وسلم مِنْ أَوَّلِهِ وَآخِرِهِ وَأَوْسَطِهِ وَانْتَهَى وَتْرُهُ إِلَى السَّحَرِ ‏.‏
Reference : Sunan an-Nasa'i 1681In-book reference : Book 20, Hadith 84