Dura lex, sed lex - "The law [is] harsh, but [it is] the law". It follows from the principle of the rule of law that even draconian laws must be followed and enforced; if one disagrees with the result, one must seek to change the law.⏎
Delegatus non potest delegare - That which has been delegated cannot delegate further.⏎
Contra non valentem agere nulla [or non] currit praescriptio - A statute of limitation does not run against those who cannot act; this is the basis of the American discovery rule limiting prescriptive limitation periods.⏎
Consuetudo pro lege servatur - "Custom is held as law". Where no laws apply to a given situation, the customs of the place and time will have the force of law.⏎