“The Prophet used to give us dates from the collection (mixed) 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
Sunan Ibn Majah Book 12, Hadith 120