Imam Malik's Muwatta, Chapter: Business Transactions

Yahya related to me from Malik from Zayd ibn Aslam from Ata ibn Yasar that Abu Rafi, the mawla of the Messenger of Allah, may Allah bless him and grant him peace, said, "The Messenger of Allah, may Allah bless him and grant him peace, borrowed a young camel and then the camels of sadaqa came to him." Abu Rafi said, "He ordered me to repay the man his young camel. I said, 'I can only find a good camel in its seventh year in the camels.' The Messenger of Allah, may Allah bless him and grant him peace, said, 'Give it to him. The best of people are those who discharge their debts in the best manner.' "