Jabir (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) said, "May Allah show mercy to a man who adopts a kind attitude when he sells, buys and demands for the repayment of loans."[Al-Bukhari]. (DE)
App reference (DE): Book 12, Hadith 84 (DE)
Arabic/English book reference (DE): Book 12, Hadith 1368 (DE)