Tashahhud Du`a – 3 (Hadith No. 796)

Salam,
Bismillah.

Volume 1, Book 12, Number 796:

Narrated Abu Bakr As-Siddiq:

I asked Allah’s Apostle to teach me an invocation so that I may invoke Allah with it in my prayer. He told me to say, “Allahumma inni zalumtu nafsi zulman kathiran, Wala yaghfirudhdhunuba illa anta faghfirli maghfiratan min ‘Indika, war-hamni innaka antal-ghafururrahim (O Allah! I have done great injustice to myself and none except You forgives sins, so please forgive me and be Merciful to me as You are the Forgiver, the Merciful).”

A relevant page here.

اللهم اني ظلمت نفسي ظلما كثيرا ولا يغفر الذنوب الا انت فاغفرلي مغفرة من عندك وارحمني انك انت الغفور الرحيم

Wassalam.