Sahih Bukhari, Chapter: Sales and Trade

Allah's Apostle forbade the selling of fruits (fresh dates) for dried dates but allowed the sale of fruits on the Araya by estimation and their new owners might eat their dates fresh. Sufyan (in another narration) said, "I told Yahya (a sub-narrator) when I was a mere boy, 'Makkans say that the Prophet allowed them the sale of the fruits on Araya by estimation.' Yahya asked, 'How do the Makkans know about it?' I replied, 'They narrated it (from the Prophet ) through Jabir.' On that, Yahya kept quiet." Sufyan said, "I meant that Jabir belonged to Medina." Sufyan was asked whether in Jabir's narration there was any prohibition of selling fruits before their benefit is evident (i.e. no dangers of being spoilt or blighted). He replied that there was none.