Sunan an-Nasa’i 1303

It was narrated from 'Abdullah bin 'Amr, from Abu Bakr As-Siddiq, may Allah (SWT) be pleased with them both, that he said to the Messenger of Allah (ﷺ):"Teach me a supplication that I may recite in my prayer." He said: "Say: 'Alahumma inni zalamtu afsi zulman kathiran wa la yaghfirudhunub illa anta faghfirli maghfiratan min 'indika warhamni innaka antalGhafurur-Rahim (O Allah, verily I have wronged myself much and there is None who forgives sins except You. Grant me forgiveness from You and have mercy on me for You are the Oft-Forgiving, Most Merciful)

It was narrated from Shadad bin Aws that:The Messenger of Allah (ﷺ) used to say in his prayer: "Allahumma inni as'aluka at-thabbuta fi al-amr wal-'azimata 'alar-rushdi wa as'aluka shukr ni'matik wa husna 'ibadatik wa as'aluka qalban saliman wa lisanan sadiqan wa as'aluka min khairi ma at'lamu wa author bika min sharri ma at'lamu wastaghfiruka lima ta'lam (O Allah, I ask You for steadfastness in all my affairs and determination in following the right path, I ask You to make me thankful for Your blessings and to make me worship You properly. I ask You for a sound heart and a truthful tongue. I ask You for the best of what You know and I seek refuge in You from the worst of what You know and I seek Your forgiveness for what You know)

Hanzalah bin 'Ali narrated that:Mihjan bin Al-Adra' narrated to him that the Messenger of Allah (ﷺ) entered the masjid and there was a man who had finished his prayer and he was reciting the tashahhud. He said: "Allahumma inni as'aluka ya Allah! Bi-annakal-Wahidul-Ahad us-Samad, alladhi lam yalid wa lam yowled, wa lam yakun lahu kufuwan ahad, an taghfirali dhunubi, innaka antal-Ghafurur-Rahim (O Allah, I ask of You, O Allah, as You are the One, the Only, the Self-Sufficient Master, Who begets not nor was He begotten, and there is None equal or comparable to Him, forgive me my sins, for You are the Oft-Forgiving, Most Merciful.)" The Messenger of Allah (ﷺ) said: "He has been forgiven," three times