By agreeing with one another to make a state by contract, men within a given area joined together, each surrendering personal freedom as necessary to promote the safety and well being of all. By this contract the members created a government. The social contract gives rights and responsibilities to both the citizenry and the government.
For example, in The United States, citizens yield the powers of prosecution of, and punishment for, criminal offenses to the judicial branch of government. The government, for its part, bears the responsibilities of maintaining public safety for the citizens through the police, court systems, correctional facilities, and all supporting structures.