Sahih Bukhari
Virtues and Merits of the Prophet (pbuh) and his Companions
Volume: 004 / Book Number: 056 / Hadith Number: 687
Narrated Abu Huraira:
Allah's Apostle said, "A man used to give loans to the people and used to say to his servant, 'If the debtor is poor, forgive him, so that Allah may forgive us.' So when he met Allah (after his death), Allah forgave him."