Sahih Bukhari Volume 3, Book 41, Hadith Number 606.
Narated By ‘Abdullah bin Ka’b bin Malik Al-Ansari : From Ka’b bin Malik that, ‘Abdullah bin Abi Hadrad Al-Aslami owed him some debt. Ka’b met him and caught hold of him and they started talking and their voices grew loudest. The Prophet passed by them and addressed Ka’b, pointing out to him to reduce the debt to one half. So, Ka’b got one half of the debt and exempted the debtor from the other half.