Musnad Ahmad 966:1

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Abu Mas‘ud, from Abu al-Sulayl, from an old woman of Banu Numayr, that she heard the Prophet, may Allah bless him and grant him peace, while he was praying with the people, and his face was toward the House (the Kaaba). She said: So I memorized from him: "O Lord, forgive me my sins and my ignorance."