The mention of wealth in which zakah is not obligatory.

The Shaykh : If that is the case, what is the zakatable wealth that we are required to pay zakah on? We say: The zakatable wealth that we are required to pay zakah on is limited, and it is not all wealth.
So there is a great deal of wealth that a person owns in which there is no zakah, such as the cars he uses for himself and the cars he uses for hire, the houses he lives in himself and the houses he prepares for rent. None of these has zakah. The clothes he wears, the utensils used by the servants, the slaves, and the maids he employs—none of these has zakah. This is because the Prophet (peace and blessings be upon him) said: So most of the wealth in our hands has no zakah.