Substantive and Procedural Laws
Substantive laws tell us what is legal and what is not, for example, a law that says people 'must buy a parking ticket'.
Procedural laws tell us how the substantive laws must be made and who is responsible, for example, a law that says 'laws about parking tickets can only be made by Parliament'.
A System of Law
A law within a legal system is not legitimate unless both the substance of what it says and the procedure by which it has been made are correct.
For example,
you may follow a law that tells you to not park on a certain part of the road (correct substance) but you wouldn't follow that law if it was simply made up by a fellow motorist (incorrect procedure).
Similarly, most people would not follow a law that told people to steal (incorrect substance), even if the law was made by Parliament (correct procedure).
Israelites are supposed to follow both the substantive and procedural laws of the Torah!
