The rule of law is an ancient ideal, and was discussed by Ancient Greek philosophers such as Plato and Aristotle around 350 BC. Plato wrote:
Where the law is subject to some other authority and has none of its own, the collapse of the state, in my view, is not far off; but if law is the master of the government and the government is its slave, then the situation is full of promise and men enjoy all the blessings that the gods shower on a state.  Law is the only element which can bring peace as well as the keeper if human right. Generally we have been hearing the term from politicians, lawyers, economists and policy-makers. They are often using the term “rule of law” to characterize a certain type of legal-political regime. It is the most important topics in the world. The ‘rule of law’ means, it is just a legal system where all level of people and organizations in a state are operated.
The rule of law, also called supremacy of law, means that the law is above everyone and it applies to everyone. Whether governor or governed, rulers or ruled, no one is above the law, no one is exempted from the law, and no one can grant exemption to the application of the law.  The rule of law means that is to apply the same law over all people in a state to protect the rights of citizens and their human freedom. In a one word we can say that no one is above the law.
2. Definition of “Rule of Law”:
Rule of law is not a just three word or it has not a single line definition. Rule of law has many different bases of meaning as well as interpretation according to different writers. On the other hand its meaning can vary between different nations and legal traditions. In the basic common sense, the rule of law is a system that attempts to keep the rights of citizens from arbitrary and offensive use of government power. Yet, in the previous discussion we have implicit that the rule of law is identical law which is applied above each person in a country whatever his title or category that’s will not be measured. Everyone is subject to the law and equal; in spite of any position in a state. A.K.Sen said about the rule of law in his “Commercial Law and Industrial Law” books that “the modern view is to apply the same law over all persons in the state and to give all persons equal rights and privileges for the protection of their human liberties”.  Rule of law – All government officials and all private citizens must follow the laws of the nation and must be treated equally under the law. The government is created by and for the people and is answerable to the people.  In addition to the formal and substantive interpretations of the term “rule of law”, another leading interpretation is the functional definition, which is consistent with the traditional English meaning that contrasts the “rule of law” with the “rule of man.” According to the functional view, a society in which government officers have a great deal of discretion has a low degree of “rule of law”, whereas a society in which government officers have little discretion has a high degree of “rule of law”  .
3. The most fundamental issues that challenge the idea if Rule of Law
3.1 Religious Issue:
According to general definition and interpretation of the rule of law, the rules and regulations are created by people who come from different religious background. On the other hand different religion has different moral and values. So, for a common law it is difficult to connect all together from various religion rules and regulation. Sometimes, there may arise a challenge between the religion’s own norm and the common legal system. Equal protection and benefit of the law without discrimination on the basis of religion may differ. Challenges generally applicable law that regulates activities in public square when those law differently impact on someone’s religious observance is certainly an important part of challenges.  In some cases, like homosexuality behavior law could not match with rule of law.
Economy is one of the most important issues that can challenge the rule of law. To run a country accurately economy is the only part which is considered as resistance power. That is for sure rule of law protects human rights and all individual are treated as equally by the ROL in a country. However in an economy system there is two types of development. One is public and other is private. In the law and development movement, the role of law was to empower the state. It was assumed that private markets were too weak to ensure growth, the state needed to play a commanding role in the economy, and law should strengthen the powers of the state. The state had to undertake many key economic roles, from banking to manufacture and state corporations were a dominant form of activity  . So for balancing the economic activities there should be rules and regulations. Therefore state has the right to make rules and regulations to control private business entity. Otherwise private business may do unfavorable activities and make money from that. “In that way, private actors would be fully empowered”  . In this circumstance the rule of law may not alien with business rules and regulations. On the other hand, there will be a chance to dictate the private economic activities by government.
The components of a good investment climate are many and varied, including macro stability, property rights, reduced crime, law and order situation, business regulation, tax and trade policy, financial markets, infrastructure, and workforce quality, industrial policy, and labor market regulation  . Hence there will be discrimination of product, price, taxes, policies ect. In economic system there are many issues that relates with rule of law. Like human right. Rule of law secures peoples right, example job, wage, working hour and other necessities. But the economic rules and regulation may not comply with, so there will be challenge for ROL. “The ability to trade does not affect everyone equally—often groups like the rural poor, indigenous groups and women are less likely to access the benefits of increased trade”  . All this may bring a challenge for the idea of Rule of Law.
Constitution is one of the most influencing issue that challenge the rule of law. A constitution is a set of rules for government—often codified as a written document—that establishes principles of an autonomous political entity. In the case of countries, this term refers specifically to a national constitution defining the fundamental political principles, and establishing the structure, procedures, powers and duties, of a government  According to the rule of law the fundamental right and liberties originate from judicial decisions. But this is one-sided view. Because, in England people have got many rights through the law of parliament and charters issued by the monarchs. Various public authorities, the Crown, the House of Parliament, the court, the administrative authorities have powers and duties and most of these are determined by statute not by the courts. So, it has been clear from the above discussion that the abolition of
discretionary power is not possible fully and also equality before law is not
possible in every case. 
3.4 Political Issue:
Political issues also challenge the rule of law. The principle of rule of law says that there should be equality before law and all are amenable to ordinary courts of the land. But this principle has many exceptions because equality before law is not possible in every case. The king or the head of the state in other countries are immune from both criminal and civil action; judges are immune from personal responsibility for their official acts even if they might have acted beyond their jurisdiction but not knowingly. 
4. Rule of law in Bangladesh
The rule of law is a basic feature of the constitution of Bangladesh. It has been pledged in the preamble to the constitution of Bangladesh that –
“It shall be fundamental aim of the state to realize through the democratic process a socialist society, free from exploitation – a society in which the rule of law, fundamental human rights and freedom, equality and justice, political economic and social, will be secured for all citizens.” 
In accordance with this pledge the following positive provisions for rule of law have been incorporated in the constitution:
Article 27 guarantees that all citizens are equal before law and are entitled to equal protection of law. Article 31 guarantees that to enjoy the protection of the law, and to be treated in accordance with law, is the inalienable right of every citizen, wherever he may be and of every other person for the time being with in Bangladesh. In Bangladesh rule of law also face some challenges-
4.1 Access to law as well as equality before it, are reserved for only those who are privileged. The rest of the population are the helpless victims of as unjust society that sets great story by privileges.
4.2 The lower courts are under the direct control of the law ministry. The judges look up to the Ministry for everything infect they are obliged to.
4.3 The government of Bangladesh continued to use the Special Power Act of 1974 and section 54 of the criminal code which allow for arbitrary arrest and preventive detention, to harass political opponents and other citizens by detaining them without formal charges.
4.4 Police is no doubt a very powerful institution for the endorsement of the rule of law. But in Bangladesh, the police have never been friendly with the public. The police serve the government and enjoy, in exchanges, the freedom to act arbitrarily and in the material interests of its own members.
4.5 According to Article 141(A) the president can declare emergency whenever he wishes. By declaring emergency in peace time the government can suspend fundamental rights and suppress the opposition movement. 
Rule of law is a very important tool to preserve the human rights. But to cope up with the modern world every government makes some exception of the rule of law. These exceptions always challenge the idea of rule of law.