Musannaf Ibn Abi Shayba 9:342

Abu al-Ahwas narrated to us, from Tariq, from Qays, from Abu ‘Asim, who said: I said to Ibn ‘Abbas: "A man has sexual intercourse with a slave girl and her daughter, both of whom are his property." He said: "One verse has forbidden them, and another verse has made them lawful, but I would not do it."