Once Bilâl brought Barnî (i.e. a kind of dates) to the Prophet (ﷺ) and the Prophet (ﷺ) asked him, "From where have you brought these?" Bilâl replied, "I had some inferior type of dates and exchanged two ' of it for one ' of Barni dates in order to give it to the Prophet (ﷺ) to eat." Thereupon the Prophet (ﷺ) said, Beware ! Beware ! This is definitely Riba (usury) ! This is definitely Riba (usury) ! Don't do so, but if you want to buy (a superior kind of dates) sell the inferior dates for money and then buy the superior kind of dates with that money." [3:506-O.B]