Decrees
The umbrella collects what UPDV says about the irrevocable royal decree — the binding edict of a Median or Persian king that, once issued, cannot be undone even by the king himself.
The unchangeable law of the Medes and Persians
Daniel's enemies trap Darius into signing an interdict against prayer to anyone but the king for thirty days. When Daniel is found praying at his window, the king's regret runs into the legal wall his own decree has built: "Then the king, when he heard these words, was intensely displeased, and set his heart on Daniel to deliver him; and he labored until the going down of the sun to rescue him" (Da 6:14). The conspirators close the gate by appealing to the law itself: "Then these [prominent] men assembled together to the king, and said to the king, Know, O king, that it is a law of the Medes and Persians, that no interdict nor statute which the king establishes may be changed" (Da 6:15). The decree is binding even on the issuer; the king's only remaining choice is to send Daniel to the lions' den and wait.