Sunan Ibn Majah, Chapter: The Chapters on Business Transactions

the Prophet (saw) asked a man to give as a loan a young camel and said: "When the camels of the Sadaqah come, we will pay you back." When the camels came, he said: "O Abu Rafi' pay this man back for his Young camel." But all I could find was a seven-year-old camel or that which is better. I told the Prophet (saw) and he said: "Give it to him, for the best of People are those who are best in repaying."