Dua from Quran : Truly, You are the One Who accepts repentance, the Most Merciful.

Bismillahirrahmanirrahim 

Dua from Quran
Rabbana wa-j'alna Muslimayni laka 

wa min Dhurriyatina 'Ummatan Muslimatan laka 

wa 'Arina Manasikana wa tub 'alayna 

'innaka 'antat-Tawwabu-Raheem

Our Lord! And make us submissive unto You 

and of our offspring a nation submissive unto You, 

and show us our Manasik (all the ceremonies of pilgrimage – Hajj and 'Umrah), 

and accept our repentance. 

Truly, You are the One Who accepts repentance, the Most Merciful. 

AL Quran , Surah Al-Baqarah (2) , 128