Sahih Muslim Book 10, Hadith Number 3781.

Chapter : Prohibition of the sale of excess water in the barren lands, and preventing people to use it, and hiring a camel to cover a she-camel.

Ka’b b. Malik reported that he made a demand for the payment of the debt that Ibn Abu Hadrad owed to him. This hadith is narrated through another chain of transmitters and (the words are):” He had to get the loan from Abdullah b. Hadrad al-Aslami. He met him and pressed him for payment. There was an altercation between them, until their voices became loud. There happened to pass by them Allah’s Messenger (may peace be upon him) and he said: O Ka’b, and pointed out with his hand in such a way as he meant half. So he got half of what he (Ibn Abu Hadrad) owed to him and remitted the half.”