Musannaf Ibn Abi Shayba 13:3143

Abu Bakr narrated to us, he said: Ibn Mahdi narrated to us, from Sa’id ibn al-Sa’ib, from Dawud ibn Abi ‘Asim, that he sold a sale to his sister on credit, then she ordered him to sell it, so he sold it. He said: So I asked Ibn al-Musayyib, and he said: "Look to see if it is you." I said: "I am he." He said: "That is usury, so do not take from her except your capital."