Sahih Bukhari Volume 3, Book 41, Hadith Number 600.

Narated By ‘Abdullah bin Ka’b bin Malik : Ka’b demanded his debt back from Ibn Abi Hadrad in the Mosque and their voices grew louder till Allah’s Apostle heard them while he was in his house. He came out to them raising the curtain of his room and addressed Ka’b, “O Ka’b!” Ka’b replied, “Labaik, O Allah’s Apostle.” (He said to him), “Reduce your debt to one half,” gesturing with his hand. Kab said, “I have done so, O Allah’s Apostle!” On that the Prophet said to Ibn Abi Hadrad, “Get up and repay the debt, to him.”