Mukhtasar Bukhari (Abridged) 474 — Supplicating before ending prayer

It is narrated from Amir al-Mu'minin Sayyiduna Abu Bakr Siddiq (may Allah be pleased with him) that he requested the Messenger of Allah (peace and blessings be upon him), "Teach me a supplication which I may recite in my prayer." So the Prophet (peace and blessings be upon him) said, "Recite this supplication: 'O Allah! I have greatly wronged myself and there is none to forgive sins except You, so forgive me with Your mercy and have mercy on me. Surely, You are the Most Forgiving, Most Merciful.'"