When is the object or consideration of an agreement unlawful?

Section 23.   What considerations and objects are lawful, and what not: The consideration or object of an agreement is lawful, unless— it is forbidden by law; or is of such a nature that, if permitted, it would defeat the provisions of any law; or is fraudulent; or involves or implies, injury to the person or property of another; or the Court regards it as immoral, or opposed to public policy. In each of these cases, the consideration or object of an agreement is said to be unlawful. Every agreement of which the object or consideration is unlawful is void.