It was narrated from Abu Rafi' that the Prophet P.B.U.H 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: "0 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 P.B.U.H and he said: "Give it to him, for the best of people are those who are best in repaying." (Sahih)