Prophet Joseph - 12:104 Yet you do not ask from them any wage. This is only a warning to the people.
What is the intention?
The Arabic Letter Sad/38:86 "Say, "I do not ask you for a wage in return for this; I am not an impostor."

The Repentance/9:34 O you who believe, most of the scribes and religious leaders eat the people´s money without right and lead them astray from the way of Allah. Give glad tidings of a painful torment to those who hoard gold and silver and spend it not in the way of Allah.

The Mountain/52:40 Or do you ask from them a wage, and this burdens them with a heavy debt?