"A constitution is an arrangement of magistracies in a state." These words of Aristotle gives us a brief introduction of what constitution is.
A constitution is a set of written rules which are acceptable to all, supreme and which carries the relationship between people and government. A constitution is more of degree of trust among people to ensure their rights and establishes the belief of equality. A constitution is like an anchor in a boat. It sets limitations on the power of ruler or elected leader. A constitution determines the right of the citizens of the respective land. Equality, justice, liberty, fraternity all these terms are usually subjective and it varies person to person but establishment should ensure all of it among the citizens of the land. So a constitution plays a vital role in this process.
Here one should also understand all countries that have constitution are not necessarily democracy, in other words all countries that have constitution are not necessarily democracy but all democracies will have constitution. 
Now if we specifically talk about India and the nature of its constitution, India being a colony of Britain, saw the unjust, inequality, disparities among citizens and society and the leaders of the freedom struggle had seen and felt the importance of the set of written rules i.e. Constitution.
The freedom struggle was not just the struggle for freedom but it was more of a social movement, the transition of politics and many more. India was partitioned on the religious basis, and the society was not even uniform. People of North were different from people of South, People of North east were different from the people of South west. Different cultures, languages, groups, tribes, religion yet a country. That was how India was and always will be. Now imagine a society of this kind without rules to ensure equality, rights etc. So, our leaders at that time formed a assembly to write the most diverse document in the history of mankind. The assembly took more than two years to write and draft the constitution. The assembly read almost every constitution, took the good things from it. There were many influencing factors of Indian constitution, such as working of British parliament, the American bill of rights, The French Revolt etc.
Now one can ask, Why should we follow some set of rules written by people who are not alive as of now? Why should we accept the rules and legislature? To understand why should we, we should look at the nature of the document which we are intending to deny. The assembly which drafted and wrote the constitution had representation of all the groups in India at that time, had appearance of all existing culture, social groups, ethnic tribes, different languages etc. So a document which has a spirit of inclusion of all and which intends and surely retains its spirit in terms of equality, rights, law, justice, liberty and fraternity, can be denied? Constitution is universally accepted in India by all the different sets of people, group, culture etc.
If we consider constitution just a set of rules to fixate the government or the degree of trust between people and establishment is also wrong. A constitution is surely more than this. A constitution plays very important role to arrange any kind of social, academic, political institutions. If there is a group of people which has some declared set of rules will surely sustain and will grow and will give productive result.
So, A system of government or institution is a boat then constitution is surely its rudder. 
(Constitutional Design, Class :- IX, NCERT) 
