Sunan Ibn Majah Book 5, Hadith 87
“The Messenger of Allah (ﷺ)
often
used to say when bowing and prostrating: ‘Subhanak Allahumma wa
bi
hamdika, Allahummaghfir li (Glory be to You, O Allah, and praise; O
Allah forgive me),’ following the command given by the
Qur’an.”[Surat
An-Nasr (110)]
“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.
“The Messenger of Allah (ﷺ) said: ‘When anyone of you bows, let him say in his bowing: “Subhana Rabbiyal-‘Azim (Glory is to my Lord, the Most Great)” three times; if he does that his bowing will be complete. And when anyone of you prostrates, let him say in his prostration, ‘Subhana Rabbiyal-A’la (Glory if to my Lord, the Most High)” three times; if he does that, his prostration will be complete, and that is the minimum.’”