The Messenger of Allah ﷺ said, "Whoever buys food must not sell it until he has taken full possession of it."Ibn Abbas said, "And I consider everything else to be like it."
أن رسول الله ﷺ قال: من ابتاع طعاما فلا يبعه حتى يستوفيه. قال ابن عباس: وأحسب كل شيء مثله.
Bukhari related it in The Book of Sales (2135), and Muslim in The Book of Sales (1525:29), both through the route of Amr bin Dinar, who heard Tawus say, "I heard Ibn Abbas say," and he related it. The wording is Muslim's.In one version, "Whoever buys food should not sell it until he has measured it out." I asked Ibn Abbas, "Why?" He said, "Do you not see that they trade gold for food on deferred terms." That is, delayed.