In claris non fit interpretatio - When a rule is clearly intelligible, there is no need of proposing a (usually extensive) interpretation.⏎
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).⏎
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.⏎
Fiat justitia et pereat mundus - "Let there be justice, though the world perish." Often used as a motto, notably by Ferdinand I, Holy Roman Emperor.⏎