When the Prophet (ﷺ) said, "Sami`a l-lahu liman hamidah," (Allah heard those who sent praises to Him), he would say, "Rabbana wa laka l-hamd." On bowing and raising his head from it the Prophet (ﷺ) used to say Takbir. He also used to say Takbir on rising after the two prostrations. (See Hadith No. 656).
Sahih al-Bukhari Book 10, Hadith 190
← Previous Hadith The Prophet (ﷺ) used to say in his bowing and prostrations, "Subhanaka l-lahumma Rabbana wa bihamdika; Allahumma ghfir li.' (Exalted Are you O Allah our Lord, and by Your praise . O Allah! Forgive me).

Sahih al-Bukhari Book 10, Hadith 189 Next Hadith → Allah's Messenger (ﷺ) said, "When the Imam says, "Sami`a l-lahu liman hamidah," you should say, "Allahumma Rabbana laka l-hamd." And if the saying of any one of you coincides with that of the angels, all his past sins will be forgiven."

Sahih al-Bukhari Book 10, Hadith 191