Sahih al-Bukhari 2239
صحيح البخاري#2239SahihNarrated Ibn `Abbas:Allah's Messenger (ﷺ) came to Medina and the people used to pay in advance the price of fruits to be delivered within one or two years. (The sub-narrator is in doubt whether it was one to two years or two to three years.) The Prophet (ﷺ) said, "Whoever pays money in advance for dates (to be delivered later) should pay it for known specified weight and measure (of the dates)
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: 35:1