Substantive law defines, in regard to a specific subject, the legal rights and relationship of people with other people or as between them and the state.
Thus, murder is an offence under Indian penal code (IPC) and is defined there in. The IPC also provides for punishment for the crime. This is known as substantive law, Similarly, the provision of the Indian contract Act,1872, are substantive in nature procedural law deals with the methods and means by which substantive law is made and administered, It lays down the rules governing the manner in which a rights is enforced under civil law (such as the Indian penal code).
Thus, provision of substantive law defines rights and duties while procedural law provides the machinery for enforcing those rights and duties.
Thus a legal action is started by taking out a writ in a civil case; by a summon or an arrest in a criminal case, and ends by the trial and judgment in the court itself, followed by the execution of the judgment.
In order to enable a statute to be valid it is necessary to follow legislative procedure. For example, Article 107 of the constitution of Indian makes provisions as to introduction and passing of Bills by the parliament.
Many a time, the distinction between substantive law and procedural law is not clear. This is because many rules classified as procedural in character might be just as easily classified as substantive as they actually affect rights and duties. Though substantive law is more important, but incorrect or improper procedures can deprive a person of his substantive rights and remedies.