Hiring/Renting: Claiming the Rental Payment or Fee
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 2205
A person who has given something on rent cannot claim the rental payment before handing over the rented item. Similarly, if a person has been hired to perform a particular task, he cannot claim his fee before performing the task except when it is normal for the fee to be paid in advance, such as when one is hired to perform hajj.
-Ayatullah Sistani, Practical Laws of Islam, Hiring/Renting (Ijarah)