Hadith 5022
Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) narrates: A man brought Barni dates to the service of the Prophet (peace and blessings of Allah be upon him). The Prophet (peace and blessings of Allah be upon him) asked, "Where did these come from?" He replied, "I bought one sa' of these in exchange for two sa'." The Prophet (peace and blessings of Allah be upon him) said, "Alas, this is pure usury. Do not do this."