Fiat justitia ruat caelum - "Let justice be done though the heavens fall." Also sometimes a motto, a legal maxim that justice must be done regardless of the result otherwise.⏎
Ignorantia juris non excusat - "Ignorance of the law is no excuse." Not knowing that one's actions are forbidden by the law is not a defense.⏎
Ex factis jus oritur - "The law arises from the facts." A principle in international law that one must take facts on the ground into account when considering the legality of certain kinds of questions.⏎
Iura novit curia - The judge knows the law (technically, there is no need to "explain the law" or the legal system to a judge/justice in any given petition).⏎