It wasnarrated from Hudhaifah bin Al-Yaman that he heard theMessenger ofAllah (ﷺ) say when he bowed:
"Subhana Rabbiyal-'Azim(Glory isto my Lord, the Most Great)" three times, and when heprostrated hesaid: "Subhana Rabbiyal-A'la (Glory is to my Lord theMost High)"three times.
English reference: Vol. 1, Book 5, Hadith 888
Arabic reference: Book 5, Hadith 938