Sahih Bukhari | Volume 3 | Hadith Number 389

Narrated by 'Abdullah bin 'Umar
Allah's Apostle said, "Do not sell fruits of dates until they become free from all the dangers of being spoilt or blighted; and do not sell fresh dates for dry dates."

Narrated Salim and 'Abdullah from Zaid bin Habit' "Later on Allah's Apostle permitted the selling of ripe fruits on trees for fresh dates or dried dates in Bai'-l-'Araya, and did not allow it for any other kind of sale."