Narrated by Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him): He said, "During the time of the Prophet (peace and blessings of Allah be upon him), we used to be given mixed dates, so we would give two sa' of them to buy one sa' of good dates. But when this reached the Prophet (peace and blessings of Allah be upon him), he said: 'Two sa' of dates for one sa' is not allowed, nor two sa' of wheat for one sa', nor two dirhams of silver for one dirham.'"