Sahih Muslim Book 10, Hadith Number 3771.

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.

Jabir b. Abdullah (Allah be pleased with them) reported Allah’s Messenger (may peace be upon him) saying: If You sell fruits to your brother (and Jabir b. Ahadith reported through another chain of narrators: If you were to sell fruits to your brother) and these is a stricken with Calamity, it is not permissible for you to get anything from him. Why do you get the wealth of your brother, without justification?