Sunan Ibn Majah 2256

It was narrated that Abu Sa’eed said:“The Prophet used to give us dates from the collection (mixed) [1] dates, and we would exchange them for dates that were better, and we add to the price. [2] The Messenger of Allah said: ‘It is not right to give one Sa of dates for two Sa, nor one Dirham for two Dirham. A Dirham for a Dirham and a Dinar for a Dinar is allowed: the only difference between them is in weight (i.e., the weight must be equal.)’” Sahih