Musannaf Ibn Abi Shayba 13:1770

Abu Bakr narrated to us, he said: Abu Mu'awiyah narrated to us, from al-A'mash, from Ibrahim, from Abd al-Rahman ibn Yazid, who said: There was a slave between me, al-Aswad, and our mother, who had witnessed the Battle of al-Qadisiyyah and had performed well in it. They wanted to emancipate him, and I was young. Al-Aswad mentioned that to Umar. Umar said: "You emancipate your shares, and let Abd al-Rahman remain on his share until he desires what you have desired, or he takes his share."