Natural Law is the law of nature. It is a simple Law. It is a Moral Law. Harm No One. Take away no one’s Natural Rights. Cause No Violence to make someone do something. Make No justifications to steal. Everything someone does or gives should be a voluntary decision.
Going against natural law is stealing someone else’s property. What is taking someone’s property? It is taking someone’s voluntary freedom of choice, body, land, food, etc. by force. Therefore, stealing means taking something that rightfully belongs to someone else. It means giving oneself the lower case right(not a real Right) to steal.
The action being justified causes harm.
The justification is man made in separation from moral law.