"Say: O Ibadi (My slaves) who have transgressed against themselves (by committing evil deeds and sins)! Despair not of the Mercy of Allah, verily Allah forgives all sins. Truly, He is Oft-Forgiving, Most Merciful" (Quran 39:53)
"And those who cry not unto any other god along with Allah, nor take the life which Allah hath forbidden save in (course of) justice, nor commit adultery - and whoso doeth this shall pay the penalty; (68) The doom will be doubled for him on the Day of Resurrection, and he will abide therein disdained for ever; (69) Save him who repenteth and believeth and doth righteous work; as for such, Allah will change their evil deeds to good deeds. Allah is ever Forgiving, Merciful. (70) [Quran 25:68-70]
Allahuma innaka 'afuwwun karimun tuhibbul 'afwa fa ‘afu anni
(O Allah! You are the Most Forgiving and Most Gracious! You love to forgive, so forgive my errors and sins)