Reference : Hisn al-Muslim 34

سُبْـحانَكَ اللّهُـمَّ رَبَّـنا وَبِحَـمْدِك ، 
اللّهُـمَّ اغْفِـرْ لي
Subḥānaka Allāhumma Rabbanā wa biḥamdika 
Allāhum-maghfir lī.

Glory is to You , O Allah , our Lord , and praise is Yours . 
O Allah , forgive me.

Reference:
Al-Bukhari 1/99, Muslim 1/350.

Chapter: While bowing in prayer