Sunan an-Nasa'i 4619

Irbad bin Saryah said:"I lent a young camel to the Messenger of Allah, and I came to ask him to repay me. He said: 'Yes, I will only repay you with a superior she-camel.' so he repaid me and repaid me well. Then a Bedouin came to him to ask to repay him a camel of a certain age, and the Messenger of Allah said: 'Give him a camel of certain age.' On that day they gave him a mature camel and he said: 'This is better than my camel.' He (The Prophet) Said:' The best of you is the one who is best in repaying