The term "rule of law" generally refers to the idea that no person is above the law. The idea extends to hold that even the government is not above the law.
In systems that do not have the rule of law, there are people and entities that can act in whatever way they want. A government official could, for example, simply declare that you had to do something (or not do something) even if there was no law that said that. A person who had enough power could break the law and get away with it because the law would not be enforced equally in all cases.
This is the opposite of what is expected in systems like those of the US, Canada, and other democratic countries. There, governments are only allowed to act in ways that are allowed by the law. The law applies to all people. We are ruled by the law and not by the whims of the people in the government.
Look at the provided link below.
Each of country in world have laws, without laws the country would collaspe because there's not exact thing for the population to follow. A country in a tree and the laws are the roots of the tree. Laws keep the country to remain stable and stay constant.
The rule of law is a legal maximum that provides that no person is above the law, that no one can be punished by the state except for a breach of the law, and that no one can be convicted of breaching the law except in the manner set forth by the law itself. The rule of law stands in contrast to the idea that the leader is above the law which was a feature of Roman law, nazi law and certain other legal systems.
But there's also a Constitutional law which has the ability stand out and change the law if needed in a vital circumstances.