Ja'far bin Iyas · Wages (Kitab Al-Ijarah)

I said: What do you think about it, Messenger of Allah? He said: A live coal between your shoulders which you have put around your neck or hanged it.

On his father's authority, said that his grandfather told that the Messenger of Allah (ﷺ) forbade the type of transactions in which earnest money was paid. Malik said: This means, as we think--Allah better knows-that a man buys a slave or hires an animal, and he says: I give you a dinar on condition that if I give up the transaction or hire, what I gave you is yours.