سنن أبي داود

Narrated Ya'la ibn Umayyah:

The Messenger of Allah (ﷺ) said to me: When my messengers come to you, give them thirty coats of mail, and thirty camels. I asked: Messenger of Allah, is it a loan with a guarantee of its return, or a loan to be paid back? He replied : It is a loan to be paid back.