سَمِعَ اللَّهُ لِمَنْ حَمِدَهُ، رَبَّنَا وَلَكَ الْحَمْدُ حَمْدًا كَثِيرًا طَيِّبًا مُبَارَكًا فِيهِ
Transliteration
Sami'allahu liman hamidahu, Rabbana wa lakal-hamdu hamdan kathiran tayyiban mubarakan fih
English meaning
Allah hears whoever praises Him. Our Lord, for You is all praise, an abundant, beautiful, blessed praise.
When is it recited?
Said while rising from bowing and then while standing upright.
Source
Bukhari, Adhan 126, 799