"The Messenger of Allah ﷺ 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 had finished praying, he said: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times." (Using translation from Nasāʾī 1736)
كَانَ رَسُولُ اللهِ ﷺ يُوتِرُ بِسَبِّحِ اسْمَ رَبِّكَ الْأَعْلَى وَقُلْ يَا أَيُّهَا الْكَافِرُونَ وَقُلْ هُوَ اللهُ أَحَدٌ فَإِذَا فَرَغَ مِنَ الصَّلَاةِ قَالَ «سُبْحَانَ الْمَلِكِ الْقُدُّوسِ» ثَلَاثَ مَرَّاتٍ