I asked Ibn ʿUmar about Salam (the fruits of) date-palms. He replied, "The Prophet ﷺ forbade the sale of dates till their benefit becomes evident and fit for eating and also the sale of silver (for gold) on credit." I asked Ibn ʿAbbas about Salam for dates and he replied, "The Prophet ﷺ forbade the sale of dates till they were fit for eating and could be estimated."

نَهَى النَّبِيُّ ﷺ عَنْ بَيْعِ النَّخْلِ حَتَّى يُؤْكَلَ مِنْهُ أَوْ يَأْكُلَ مِنْهُ وَحَتَّى يُوزَنَ