1740. Sunan an-Nasa’i Chapter: Encouragement to pray in houses and the virtue of doing so; Book 20, Hadith 143

Muhammad bin Bashshar informed us, he said: “Abu Dawud narrated to us from Shu’bah, from Qatadah, who said: I heard ‘Azarah narrating from Sa’eed bin ‘Abdur-Rahman Ibn Abza, from his father
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 had finished praying, he said: Subhanal-Malikil-Quddus (Glory be to the Sovereign, the Most Holy) three times.”