The Messenger of Allah ﷺ often said while bowing and prostrating himself; “Glory be to Thee, O Allah, out Lord.” And “Praise be to Thee, O Allah, forgive me,” Thus interpreting the (command in the Qur’an). (Using translation from Abū Dāʾūd 877)
أَنَّ رَسُولَ اللهِ ﷺ كَانَ يُكْثِرُ أَنْ يَقُولَ فِي رُكُوعِهِ وَسُجُودِهِ سُبْحَانَكَ اللهُمَّ رَبَّنَا وَبِحَمْدِكَ اللهُمَّ اغْفِرْ لِي