Sahih Bukhari Volume 001, Book 008, Hadith Number 447.
Narated By Ka'b : In the mosque l asked Ibn Abi Hadrad to pay the debts which he owed to me and our voices grew louder. Allah's Apostle heard that while he was in his house. So he came to us raising the curtain of his room and said, "O Ka'b!" I replied, "Labaik, O Allah's Apostle!" He said, "O Ka'b! reduce your debt to one half," gesturing with his hand. I said, "O Allah's Apostle! I have done so." Then Allah's Apostle said (to Ibn Abi Hadrad), "Get up and pay the debt to him."