Daniel 6:15

Then these men assembled to the king
Who had left him for a while to consider of the case; or they departed to consult among themselves about the king's proposals to them; or went home to their own houses to dinner, and returned in a body; they came in a tumultuous way, as the word signifies; see ( Daniel 6:6 ) , they cluttered about him, and were very rude and noisy, and addressed him in an authoritative and threatening manner: and said unto the king, know O king, that the law of the Medes and
Persians is, that no decree nor statute which the king establisheth
may be changed;
they perceived that he was desirous of altering or nullifying the decree he had made, which to have done would have been to his reputation; and to this they oppose a fundamental law of the realm, that no decree ratified by the king could be altered; to attempt to do this would be a breach of their constitution, and of dangerous consequence; it would lessen the king's authority, and be a means of his subjects rising up in rebellion against him: for that there was such a law, the king knew as well as they; nor do they say this by way of information, but to urge him to the execution of the decree; and there is no doubt to be made that there was such a fundamental law, though a foolish one, and which afterwards continued, ( Esther 1:19 ) , but the instance which some writers give out of Diodorus Siculus ^F6, concerning Charidemus, a general of the Athenians, whom another Darius king of Persia condemned to die for the freedom of speech he used with him and afterwards repented of it, but in vain; for his royal power, as the historian observes, could not make that undone which was done; this is no proof of the immutability of the laws of the Persians, since the king's repentance was after the general's death, which then was too late.