The last time he extended his voice, he said -
رَبُّ الْمَلَائِكَةِ وَالرُّوحِ
Pronunciation
Rabbul-malaa'ikati warrooh
Meaning
Lord of the angels and the Spirit.
Source: Sunan Daraqutni 2/31, Mu'jamul Awsat 8/108, Sunan Bayhaqi 3/40
Read the hadith
حَدَّثَنَا عُثْمَانُ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا مُحَمَّدُ بْنُ أَبِي عُبَيْدَةَ، حَدَّثَنَا أَبِي، عَنِ الأَعْمَشِ، عَنْ طَلْحَةَ الأَيَامِيِّ، عَنْ ذَرٍّ، عَنْ سَعِيدِ بْنِ عَبْدِ الرَّحْمَنِ بْنِ أَبْزَى، عَنْ أَبِيهِ، عَنْ أُبَىِّ بْنِ كَعْبٍ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا سَلَّمَ فِي الْوِتْرِ قَالَ " سُبْحَانَ الْمَلِكِ الْقُدُّوسِ " .
Narrated Ubayy ibn Ka'b: When the Messenger of Allah (ﷺ) offered salutation in the witr prayer, he said: Glorify be to the king most holy. Sunan Abi Dawud 1430 [Sunane Dara Kutni 2/31, Mo'jamul Awsat 8/108, Sunan Baihaqi 3/40]
Duas from IslamicAPI's Masnun Dua dataset (based on the Quran, hadith, Hisnul Muslim and Rahe Belayat). See the dataset