Sahih Bukhari

Narrated Tawus:Ibn `Abbas said, ""Allah's Messenger (ﷺ) forbade the selling of foodstuff before its measuring and transferring into one's possession."" I asked Ibn `Abbas, ""How is that?"" Ibn `Abbas replied, ""It will be just like selling money for money, as the foodstuff has not been handed over to the first purchaser who is the present seller