Mentioning the different wordings in the reports from Ubayy bin Ka'b concerning witr
أَخْبَرَنَا عَلِيُّ بْنُ مَيْمُونٍ، قَالَ حَدَّثَنَا مَخْلَدُ بْنُ يَزِيدَ، عَنْ سُفْيَانَ، عَنْ زُبَيْدٍ، عَنْ سَعِيدِ بْنِ عَبْدِ الرَّحْمَنِ بْنِ أَبْزَى، عَنْ أَبِيهِ، عَنْ أُبَىِّ بْنِ كَعْبٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ يُوتِرُ بِثَلاَثِ رَكَعَاتٍ كَانَ يَقْرَأُ فِي الأُولَى بِـ { سَبِّحِ اسْمَ رَبِّكَ الأَعْلَى } وَفِي الثَّانِيَةِ بِـ { قُلْ يَا أَيُّهَا الْكَافِرُونَ } وَفِي الثَّالِثَةِ بِـ { قُلْ هُوَ اللَّهُ أَحَدٌ } وَيَقْنُتُ قَبْلَ الرُّكُوعِ فَإِذَا فَرَغَ قَالَ عِنْدَ فَرَاغِهِ " سُبْحَانَ الْمَلِكِ الْقُدُّوسِ " . ثَلاَثَ مَرَّاتٍ يُطِيلُ فِي آخِرِهِنَّ .
It was narrated from Ubayy bin Ka'b that: The Messenger of Allah (ﷺ) used to pray witr with three rak'ahs. In the first he would recite: "Glorify the Name of Your Lord, the Most High" in the second: "Say: O you disbelievers!", and in the third: "Say: He is Allah, (the) One". And he would say the Qunut before bowing, and when he finished he would say: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times, elongating the words the last time.