Sunan an-Nasa'i #1701 · The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day

Sunan an-Nasa'iIt was narrated that Ubayy bin Ka'b 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) used to recite: "Glorify the Name of Your Lord, the Most High;" in witr, in the second rak'ah he would recite: "Say: O you disbelievers!"; and in the third "Say: He is Allah, (the) One". And he only said the taslim at the end, and he would say- meaning after the taslim: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy)' three times
أَخْبَرَنَا يَحْيَى بْنُ مُوسَى، قَالَ أَنْبَأَنَا عَبْدُ الْعَزِيزِ بْنُ خَالِدٍ، قَالَ حَدَّثَنَا سَعِيدُ بْنُ أَبِي عَرُوبَةَ، عَنْ قَتَادَةَ، عَنْ عَزْرَةَ، عَنْ سَعِيدِ بْنِ عَبْدِ الرَّحْمَنِ بْنِ أَبْزَى، عَنْ أَبِيهِ، عَنْ أُبَىِّ بْنِ كَعْبٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَقْرَأُ فِي الْوَتْرِ بِـ ‏{‏ سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى ‏}‏ وَفِي الرَّكْعَةِ الثَّانِيَةِ بِـ ‏{‏ قُلْ يَا أَيُّهَا الْكَافِرُونَ ‏}‏ وَفِي الثَّالِثَةِ بِـ ‏{‏ قُلْ هُوَ اللَّهُ أَحَدٌ ‏}‏ وَلاَ يُسَلِّمُ إِلاَّ فِي آخِرِهِنَّ وَيَقُولُ يَعْنِي بَعْدَ التَّسْلِيمِ ‏
"‏ سُبْحَانَ الْمَلِكِ الْقُدُّوسِ ‏"‏ ‏.‏ ثَلاَثًا ‏.‏
Reference : Sunan an-Nasa'i 1701In-book reference : Book 20, Hadith 104