Ata bin Abu Rabah reported: Abu Said al-Khudri (RA) met Ibn Abbas (RA) and said to him: What do you say in regard to the conversion (of commodities or money) did you hear it from Allahs Messenger ﷺ , or is it something which you found In Allahs Book, Majestic and Glorious? Thereupon Ibn Abbas (RA) (Allah be pleated with them) said: I dont say that. So far at Allahs Massenger ﷺ is concerned, you know him better, and to far as the Book of Allah to concerned, I do not know it (more than you do), but Usama bin Zaid (RA) narrated to me Allahs Messenger ﷺ as having said this: Beware, there can be an element of interest in credit.