Musannaf Ibn Abi Shayba 13:1939

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Sufyan narrated to us, from ‘Amr ibn Dinar, from al-Zuhri, from a man from the Ansar, that ‘Umar ibn al-Khattab emancipated a foundling (laqit).