Musannaf Ibn Abi Shaybah 22958 — Selling umm walad slave women

It is narrated from Maymun bin Mihran that word spread in the army of Umar bin Abd al-Aziz that Umar bin Abd al-Aziz considered the sale of an umm walad permissible. Then a man came to him and asked about this. It then became clear that Umar bin Abd al-Aziz held to the freeing of an umm walad more firmly than the man who was asking, and that in the view of Umar bin Abd al-Aziz this was also the opinion of Sayyiduna Umar bin al-Khattab (may Allah be pleased with him).