Abu Qilabah (may Allah have mercy on him) said: In Basrah, in the time of Ziyad, people used to take dirhams for dinars on credit. So a man from the Companions of the Prophet (peace and blessings be upon him), who was called Hisham bin Amir al-Ansari (may Allah be pleased with him), stood up and said: "The Messenger of Allah (peace and blessings be upon him) forbade selling gold for silver on credit, and he informed us that this is usury (riba)."
Hadith Referenceالمعجم الكبير للطبراني / باب الهاء / 18679