Sahih al-Bukhari 2182
صحيح البخاري#2182SahihNarrated `Abdur-Rahman bin Abu Bakra:that his father said, "The Prophet (ﷺ) forbade the selling of gold for gold and silver for silver except if they are equivalent in weight, and allowed us to sell gold for silver and vice versa as we wished
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 34:130