Musannaf Ibn Abi Shaybah 24949 — A man who exchanges dinars

Rabi' bin Sa'd said: I asked Abu Ja'far about a man from whom I bought foodstuff. He gave me part of it, then he ran short and did not give me the rest, and he says: Sell me your foodstuff so that I may pay you. He said: Do not go near this transaction; it is clear usury (riba).