Muawiya wrote to Abdul-Rahman bin Shibl, instructing him to teach the people what he had heard from the Messenger of Allah ﷺ. So he gathered them together and said, "I heard the Messenger of Allah ﷺ say, 'Merchants are the wrongdoers.'"They said, "Messenger of Allah, has Allah not made trade lawful and forbidden riba?"He replied, "Yes, but they swear oaths and so fall into sin."
ثم قال إن التجار هم الفجار قالوا يا رسول الله أليس قد أحل الله البيع وحرم الربا قال بلى ولكنهم يحلفون ويأثمون