"The Messenger of Allah ﷺ often used to say when bowing and prostrating: 'Subhanaka Rabbana wa bi Hamdika, Allahumm aghfirli (Glorfy and praise be to You, our Lord. O Allah, forgive me.).'"  

كَانَ رَسُولُ اللَّهِ ﷺ يُكْثِرُ أَنْ يَقُولَ فِي رُكُوعِهِ وَسُجُودِهِ سُبْحَانَكَ رَبَّنَا وَبِحَمْدِكَ اللَّهُمَّ اغْفِرْ لِي