Musannaf Ibn Abi Shaybah 17047 — A man who owns two sisters as slaves

Sayyiduna Uthman (may Allah be pleased with him) was asked: If a man owns two sisters and has had intercourse with one of them, may he have intercourse with the other? He said: One verse has made them lawful and another has made them forbidden. However, I neither command it nor forbid it. Then the questioner met Sayyiduna Ali (may Allah be pleased with him) at the door and asked him about the same matter, and he said: I forbid you from it, and if I had power over you and you did it, I would punish you.