Sunan an-Nasa'i, Book 20, Hadith 135 (In-Book) ⓘ

Bahz bin Asad, said: "Shu'bah narrated to us, from Salamah and Zubaid, from Dharr, from Ibn Abdur-Rahman bin Abza from his father that the Messenger of Allah used to recite in Witr: "Glorify the Name of your Lord, the Most High;" and "Say: O you disbelievers!;' and 'Say: He is Allah, (the) One.' And when he said the taslim, he would say: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times, raising his voice the third time."

أَخْبَرَنَا عَمْرُو بْنُ يَزِيدَ، قَالَ حَدَّثَنَا بَهْزُ بْنُ أَسَدٍ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ سَلَمَةَ، وَزُبَيْدٍ، عَنْ ذَرٍّ، عَنِ ابْنِ عَبْدِ الرَّحْمَنِ بْنِ أَبْزَى، عَنْ أَبِيهِ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُوتِرُ بِـ ‏{‏ سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى ‏}‏ وَ ‏{‏ قُلْ يَا أَيُّهَا الْكَافِرُونَ ‏}‏ وَ ‏{‏ قُلْ هُوَ اللَّهُ أَحَدٌ ‏}‏ وَكَانَ يَقُولُ إِذَا سَلَّمَ ‏"‏ سُبْحَانَ الْمَلِكِ الْقُدُّوسِ ‏"‏ ‏.‏ ثَلاَثًا وَيَرْفَعُ صَوْتَهُ بِالثَّالِثَةِ ‏.‏