Musannaf Ibn Abi Shayba 13:495

Abu Bakr narrated to us, he said: Abu al-Ahwas narrated to us, from Simak, from Abu Ubaydah or from Abd al-Rahman ibn Abd Allah, from Ibn Mas’ud, who said: "Two bargains in one bargain is usury (riba); it is for a man to say: 'If it is for cash, then it is for such-and-such, and if it is on credit, then it is for such-and-such.'"