Sunan Ibn Majah Book 5, Hadith 85
“When the following was revealed:
‘So
glorify the Name of your Lord, the Most Great’, the
Messenger of Allah (ﷺ) said to us: ‘Say this in your Ruku’.’
And
when the following was revealed: ‘Glorify the Name of your
Lord, the
Most High.’ the Messenger of Allah (ﷺ) said to
us: ‘Say this
in your prostrations.’”
“We used to feel sorry for the Messenger of Allah (ﷺ) because he took pains to keep his arms away from his sides when he prostrated.”
“Subhana Rabbiyal-‘Azim (Glory is to my Lord, the Most Great)” three times, and when he prostrated he said: “Subhana Rabbiyal-A’la (Glory is to my Lord the Most High)” three times.