What is the legal ruling on registering a car in the name of a person while he knows it is not his property, and he signs an acknowledgment and undertaking to that effect? And is the money he takes in exchange for this registration lawful or unlawful?

That is not permissible for several reasons: - The laws regulating car ownership must not be violated. - It involves exposing oneself and one's property to loss and destruction, and the Prophet, peace and blessings be upon him, forbade humiliating oneself and squandering wealth. - Taking money in exchange for registering the car in your name falls under the price of status (thaman al-jah), which is not permissible.

The obligation is to rectify this violation by purchasing the car for the amount they paid for it, or for its market value, or by selling it and giving them its price. Alternatively, one can buy a car and lease it to them.