(4) باب السَّلَمِ فِي النَّخْلِ
Narrated Abu Al-Bakhtari:
I asked Ibn `Umar about Salam for dates. Ibn `Umar replied, "The Prophet (ﷺ) forbade the sale (the fruits) of date-palms until they were fit for eating and also forbade the sale of silver for gold on credit." I also asked Ibn `Abbas about it. Ibn `Abbas replied, "The Prophet (ﷺ) forbade the sale of dates till they were fit for eating, and could be weighed." I asked him, "What is to be weighed (as the dates are on the trees)?" A man sitting by Ibn `Abbas said, "It means till they are cut and stored."
Reference: Sahih al-Bukhari 2249, 2250
In-book reference: Book 35, Hadith 11
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 35, Hadith 452