People used to buy food in bulk without measuring at the upper part of the market, so the Messenger of Allah ﷺ forbade them from selling it until they had transported it.
حدثنا أحمد بن حنبل حدثنا يحيى عن عبيد الله أخبرني نافع
كانوا يتبايعون الطعام جزافا بأعلى السوق فنهى رسول الله ﷺ أن يبيعوه حتى ينقلوه
Bukhari narrated it in the Book of Sales, Chapter on the limit of meeting traders before they reach the market, no. 2167, from the hadith of Yahya Qattan, and Muslim narrated it, no. 34/1526, from the hadith of Ubaydullah, with the same wording. See the previous hadith. It is also found in Musnad Ahmad, 2/15.