Wages (Kitab Al-Ijarah)
Dawud :: Book 23 : Hadith 3559
Narrated Ya'la ibn Umayyah:
The Apostle of Allah (peace_be_upon_him) said to me: When my messengers come to you, give them thirty coats of mail, and thirty camels. I asked: Apostle 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.