It is narrated from Hazrat Abu Saeed (may Allah be pleased with him) that a date seller brought some dates to the service of the Prophet (peace and blessings be upon him). The Prophet (peace and blessings be upon him) found something unusual about them, so he asked him, "Where did you get these from?" He said, "We gave two sa’ of our dates and took one sa’ of these good dates." The Prophet (peace and blessings be upon him) said, "You have engaged in a usurious transaction."