Sahih Muslim Book 10, Hadith Number 3774.

Chapter : It is forbidden for a solvent to make delay in the payment of debt and the desirability of a reference, and it is excellent for the rich man to accept that when reference is made to him.

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?