Musnad Abu Ya'la al-Mawsili 1:31

Ubayd Allah ibn Umar al-Qawariri narrated to us, Hisham ibn Abd al-Malik and Asim ibn Ali narrated to us, they said: al-Layth narrated to us, from Yazid ibn Abi Habib, from Abu al-Khayr, from Abdullah ibn Amr, from Abu Bakr—and the wording is for the hadith of Ghassan—that he said to the Messenger of Allah (may Allah bless him and grant him peace): "Teach me a supplication that I may supplicate with in my prayer." He said: "O Allah, indeed I have wronged my soul with much wrongdoing"—and in the hadith of al-Qawariri alone, from Asim: "great wrongdoing"—"and none forgives sins except You, so forgive me with a forgiveness from You, and have mercy upon me; indeed, You are the Forgiving, the Merciful." Abu Ya'la said: Al-Layth said: "From Abu Bakr al-Siddiq," and Amr ibn al-Harith said: "From Abdullah ibn Amr," and he did not exceed it.