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.⏎
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).⏎
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.⏎
Ex turpi causa non oritur actio - "From a dishonorable cause an action does not arise." A party cannot bring a legal action for consequences of his own illegal act.⏎