Musannaf Ibn Abi Shayba 13:2554

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Sufyan narrated to us, from Mughira, from Shibak, from Ibrahim, from Shurayh, who said: It is more beloved to me in currency exchange (sarf) that they both depart while there is no confusion between them.