[Machine] The Prophet of Allah, ﷺ , used to perform three voluntary units of prayer without reciting the final salutation in them until he completed the first unit by saying "Subhan Rabbi al-A'la" (Glory be to my Lord, the Most High), the second unit by saying "Qul ya ayyuha al-kafiroon" (Say, O disbelievers), and the third unit by saying "Huwa Allahu ahad" (He is Allah, the One). He would prolong the recitation before bowing down, and when he finished, he would say "Subhan al-Malik al-Quddus" (Glory be to the King, the Holy) twice, and in the third unit, he would raise his voice.
أَنَّ رَسُولَ اللهِ ﷺ كَانَ يُوتِرُ بِثَلَاثِ رَكَعَاتٍ لَا يُسَلِّمُ فِيهِنَّ حَتَّى يَنْصَرِفَ الْأُولَى بِسَبِّحِ اسْمَ رَبِّكَ الْأَعْلَى وَالثَّانِيَةِ بِقُلْ يَا أَيُّهَا الْكَافِرُونَ وَالثَّالِثَةِ بِقُلْ هُوَ اللهُ أَحَدٌ وَقَنَتَ قَبْلَ الرُّكُوعِ فَلَمَّا انْصَرَفَ قَالَ سُبْحَانَ الْمَلِكِ الْقُدُّوسِ مَرَّتَيْنِ وَرَفَعَ صَوْتَهُ فِي الثَّالِثَةِ