Legality

   Legality is the final part of any contract.  It is also the part of the contract that can expose the real intentions of a party and what they plan on doing.  Legality is basically a proof reading over a contract. Its the part of the contract that checks to see if any of the laws have been violated as well as make sure that everything that has been agreed upon is in the contract.  A court will not help any parties that are in an illegal contract instead they will just leave them at the spot that they got themselves too.  This also means that neither party can enforce the agreement on each other.  The court may intervene if there is one party that is at less fault then other if it is getting back property or money.  For example if the offeror were to get one of his friends entered into a contract with him for selling guns on the black market this contract is no longer legal because they have just violated a law by selling arms illegally.

http://stevenclark.com.au/2009/11/09/contracts-101-part-3-the-six-elements/