جامع الترمذي

Narrated 'Abdullah bin Yazid:

"Zaid, Abu Ayyash asked Sa'd regarding white wheat in exchange for barley: which of them was better ? He said the white, then he forbade that. Sa'd said: 'I heard the Messenger of Allah (ﷺ) being asked about selling dried dates for ripe dates and he said to those present: "Will the fresh dates shrink when they are dry ?" They said yes, so he forbade that.'"