It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) said: "None of you should sell over the sale of his brother," and the Prophet (peace and blessings be upon him) forbade deception in sales, the sale of the unborn offspring of a pregnant animal, and the sale of muzabana. Muzabana means that fruits are sold in exchange for dates by measure, or grapes are sold in exchange for raisins by measure.