صحيح مسلم

Ata' b. Abu Rabah reported: Abu Sa'id al-Khudri (Allah be pleased with them) met Ibn 'Abbas (Allah be pleased with them) and said to him: What do you say in regard to the conversion (of commodities or money) did you hear it from Allah's Messenger (ﷺ), or is it something which you found In Allah's Book, Majestic and Glorious? Thereupon Ibn Abbas (Allah be pleated with them) said: I don't say that. So far at Allah's 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 b. Zaid (Allah be pleased with him) narrated to me Allah's Messenger (ﷺ) as having said this: Beware, there can be an element of interest in credit.