Riyad as-Salihin: The Book of the Remembrance of Allah – Hadith No. 745 — Ali (May Allah be pleased with him) reported: When the Messenger of Allah (ﷺ)… (Hadith No. 745)

'Ali (May Allah be pleased with him) reported: When the Messenger of Allah (ﷺ) was in Salat (prayer), he used to supplicate towards the end of prayer after Tashahhud and before the concluding salutations: "Allahum-maghfir li ma qaddamtu wa ma akh-khartu, wa ma asrartu, wa ma a'lantu, wa ma asraftu, wa ma Anta a'lamu bihi minni. Antal-Muqqadimu, wa Antal-Mu'akh-khiru. La ilaha illa Anta (O Allah! Forgive my former and latter sins, which I have done secretly and those which I have done openly, and that I have wronged others, and those defaults of mine about which You have better knowledge than I have. You Alone can send whomever You will to Jannah, and You Alone can send whomever You will to Hell-fire. None has the right to be worshipped but You.".

Explanation:

Reference: Riyad as-Salihin, The Book of the Remembrance of Allah, Hadith No. 745