Sahih Muslim
The Book of Transactions (Kitab Al-Buyu)
Book Number: 010 / Hadith Number: 3774
Anas b. Malik (Allah be pleased with him) reported that Allah's Messenger (may peace be upon him) forbade the sale of fruits until these are mellow. They (the companions of Anas) said: What is meant by" mellow"? He said: It implies that these became red. He said: When Allah hinders the growth of fruits, (then) what for the wealth of your brother would become permissible for you?