Sahih Muslim | Book 10 | Hadith Number 3642

Narrated by Ibn Abbas (Allah be pleased with them)
Ibn Abbas (Allah be pleased with them) reported Allah's Messenger (may peace be upon him) as saying: He who buys food-rain should not sell it until he has taken possession of it. Ibn Abbas (Allah be pleased with them) said: I regard everything like food (so far as this principle is concerned).