"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 said the taslim, he would say: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times, elongating his words the third time."
Sunan an-Nasa'i Book 20, Hadith 137
← Previous Hadith "Shu'bah narrated to us, he said: Salamah and Zubaid informed me, from Dharr, from Ibn 'Abdur-Rahman bn Abza from Abdur-Rahman, that 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 said the taslim, he would say: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times, raising his voice with Subhanal-Malikil-Quddus the third time."

Sunan an-Nasa'i Book 20, Hadith 136 Next Hadith → "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.'"

Sunan an-Nasa'i Book 20, Hadith 138