Musnad Ahmad 487:4

Yazid ibn Harun narrated to us, Hisham ibn Hassan, Shu'bah, and Sharik informed us, from Ya'la ibn 'Ata, from Jabir ibn Yazid, from his father, who said: We prayed the dawn prayer with the Messenger of Allah, may Allah bless him and grant him peace, in the Mosque of Al-Khayf. Then he mentioned the hadith. He said: Sharik said in his hadith: One of them said: "O Messenger of Allah, ask for forgiveness for me." He said: "May Allah forgive you."