What is Law??

Law is a system of rules, usually enforced through a set of institutions. It shapes politics, economics and society in numerous ways and serves as a primary social mediator of relations between people.
From Wikipedia.



why is it we need Law... ??

Its possible to describe law as body of official rules and regulations. Law is also used to govern a society and to control the behavior of the people, so law is a formal mechanism of social control.
In my opinion i think this is best to describe y do we need law.