Musannaf Ibn Abi Shayba 3:3735

6112. Rawh ibn ‘Ubadah narrated to us, he said: Ibn Jurayj informed me, from ‘Abd Allah ibn ‘Ubayd Allah ibn Abi Mulaykah, that they used to come to ‘A’ishah—and his father, and ‘Ubayd ibn ‘Umayr, and al-Miswar ibn Makhramah, and many people—and Abu ‘Amr, the freed slave of ‘A’ishah, would lead them in prayer. And Abu ‘Amr at that time was a young boy who had not yet been manumitted.