Sunan At-Tirmidhi
Hadith #1316
Narrated Abu Hurairah: ""The Messenger of Allah (ﷺ) took a camel of a particular age on loan. He gave back to him a camel of a better age than the one he was given. He said: 'The best among you is the best in repaying.'"" He said: There is something on this topic from Abu Rafi'. [Abu 'Eisa said:] The Hadith of Abu Hurairah is a Hasan Sahih Hadith. Shu'bah and Sufyan reported it from Salamah. This is acted upon according to some of the people of knowledge, they saw no harm is taking a camel of a particular age as a loan. This is the view of Ash-Shafi'i, Ahmad, and Ishaq. But some of them disliked that