Volume 3, Book 38, Number 506:
Narrated Abu Said al-Khudri:
Once Bilal brought Barni (i.e. a kind of dates) to the Prophet and the Prophet asked him, “From
where have you brought these?” Bilal replied, “I had some inferior type of dates and exchanged two
Sas of it for one Sa of Barni dates in order to give it to the Prophet; to eat.” Thereupon the Prophet
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 su –
perior kind of dates with that money.”