Musannaf Ibn Abi Shayba 13:325

Waki’ narrated to us, from Sufyan, from ‘Ammar al-Duhni, who said: I witnessed Shurayh, and ‘Abd [a slave] testified before him regarding a house, so he accepted his testimony. It was said to him: "He is a slave." He replied: "All of us are slaves, and our mother is Eve."