It is narrated from Hazrat Zaid bin Abu Ayyash that he asked Sayyiduna Sa’d bin Abi Waqqas (may Allah be pleased with him) whether barley can be sold in exchange for sult (a type of grain that is between wheat and barley, produced in Ghor and Hijaz). He said: Which of the two is better? He replied: Barley. So he forbade it, and Sayyiduna Sa’d (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him), people asked him about selling dry dates in exchange for fresh dates. The Messenger of Allah (peace and blessings be upon him) said:“When fresh dates dry, does their weight decrease?”The people said: Yes. Then the Messenger of Allah (peace and blessings be upon him) forbade it.