Musannaf Ibn Abi Shayba 13:3200

Abu Bakr narrated to us, he said: Isa ibn Yunus narrated to us, from Amr, the freed slave of Afra, who said: I asked Sa’id ibn al-Musayyib about two men who entered into a partnership, and one of them paid on behalf of his companion the price [of goods]. Then they arrived in Medina and sold a portion of the wheat and made a profit, and a portion remained. The one who had paid the money said to his companion: "If you wish, you may pay [your share of] what remains and you remain in your partnership; and if you wish, you may exit from it and from its profit, and I will release you [from the debt]." He [Sa’id] said: "This is not permissible." And I asked al-Qasim, and he said the same.