Messenger v. Mason was a United States Supreme Court case that was decided in 1870. The case involved a dispute between two parties over the ownership of a piece of land in the state of Ohio. The plaintiff, Messenger, claimed that he had purchased the land from the defendant, Mason, in 1867. Mason, however, argued that he had never sold the land to Messenger and that Messenger had no legal right to the property. The Supreme Court ultimately sided with Messenger, ruling that he had a valid claim to the land. The Court found that Messenger had provided sufficient evidence to prove that he had purchased the land from Mason in 1867. The Court also found that Mason had failed to provide any evidence to support his claim that he had never sold the land. As a result, the Court ruled in favor of Messenger and granted him ownership of the land.

In Messenger v. Mason, the Supreme Court was asked to decide whether a contract between two parties could be enforced if it had been made without consideration. The majority opinion held that contracts must have consideration in order for them to be enforceable, and thus ruled against the plaintiff's claim. However, Justice Field dissented from this ruling on the grounds that there were certain circumstances where an agreement should still be considered binding even when not supported by consideration. He argued that agreements which are based upon moral obligations or natural justice should still remain valid despite lack of consideration because they represent a higher standard of fairness than what is required by law alone. Furthermore, he believed that such agreements would encourage people to act honorably towards one another and promote trustworthiness within society as a whole.