A "law" is a legal rule that is usually written down and enforced by someone in authority. A "principle" is a guideline for decision-making and behavior.
* This meaning of "law" is different from its meaning in the term, "law of Moses" where it refers to commands and instructions that God gave the Israelites.
* When a general law is being referred to, "law" could be translated as "principle" or "general rule."