A government creates and enforces the laws that protect the rights and lives of citizens and discourages crime by punishing delinquents. Government provides an ordered, systematic way to ensure the safety of the citizenry. Without a government, people would be less likely to respect contracts and agreements with one another due to the lack of an objective way to settle disputes.
Government creates laws dictating the proper relationships between citizens. It stipulates that theft, murder, assault and a number of other actions are illegal. Government establishes consequences for those who violate these laws and enforces its laws through the police and military. In this way, government keeps the peace. Criminals know that if they break society's rules, punishment awaits. Those who disregard the law and violate the rights of others can be imprisoned and executed, preventing them from causing further harm.
Government also serves as an arbiter between disagreeing parties. When two or more parties have a dispute, they go to a court, a government entity, that decides the case and enforces its decision with the power of government. Without an impartial, authoritative arbiter with the power to enforce rulings, people would have nowhere to turn to settle disputes. In some cases, injured parties would have no way of proving wrongs against them. In other cases, angered individuals may take judgment into their own hands and resort to extreme measures, such as violence and vigilantism.