The law should protect us from the will of the rulers, arbitrary decisions of the elected or non-elected politicians, any of us acting in an anti-social way, as well as any wrongdoing. Classical liberals are simply striving for a lawful society.
They argue that the government has an important role to play in the rule of law, especially in terms of protecting human life, personal liberty, the integrity of a person and his or her property. They also believe that the law should not criminalize the so-called consensual crimes in which there is no second victim, such as in the case of voluntary drug use or voluntary prostitution.
In the context of European continental law, which is based on the Roman law, we tend to talk about public and private law. While public law concerns the interests of the government and has a relationship of superiority (public authority) and subordination (private persons), private law regulates the mutual affairs of people who act as equal persons in legal relations.
According to classical liberals, a free society is built mainly on the norms of private law which dominates by the branches of civil and commercial law, and also on the rules of criminal law protecting the individual from violence, fraud or crime. Private individuals should be able to do anything that is not prohibited by law, while public authorities can only do what the law explicitly allows them to do.
Classical liberals argue that traditional private law institutes which dominate the sectors of civil and commercial law can be very useful in solving problems that public sectors, such as environmental law, cannot cope with.
As far as government or constitutional law is concerned, liberals support the idea of a limited constitutional government. They prefer the rule of law, which is the command of impersonal written and unwritten rules, and not the arbitrariness of the individual, the connections or the acquaintance.
The societal order is based on rules that are abstract, generally applicable and worded negatively – as prohibitions. This means that they do not impose on people the specific requirements they are to fulfil, but rather enable them to achieve their own goals without compromising the legitimate interests of others.
In conclusion, I will only repeat that the classical liberals favor rules only speaking about what is prohibited, rather than explicitly setting out what must be done. Classical liberal motto is the rule of law, a motto which was often repeated by F. A. Hayek.