Lex retro non agit - "The law does not operate retroactively." A law cannot make something illegal that was legal at the time it was performed. See ex post facto law.⏎
Nemo ius ignoratur censetur - "Not knowing the law is harmful." Everyone should know the law. This is used in European Law-countries with a history of Roman law, the 'sentence' was first made by Aristotle.⏎
Lex specialis derogat legi generali - "A law governing a specific subject matter overrides a law which only governs general matters."⏎
Lex posterior derogat priori - "Later law removes the earlier." More recent law overrules older ones on the same matter.⏎
Leges humanae nascuntur, vivunt, moriuntur - "The laws of man are born, live, and die." Illustrates that laws are made, are in force for a period, and then become obsolete.⏎