It pleased Darius to set over the kingdom a hundred and twenty satraps, to be throughout the whole kingdom; and over them three presidents, of whom Daniel was one, to whom these satraps should give account, so that the king mighty suffer no loss. Then this Daniel became distinguished above all the other presidents and satraps, because an excellent spirit was in him; and the king planned to set him over the whole kingdom. Then the presidents and the satraps sought to find a ground for complaint against Daniel with regard to the kingdom; but they could find no ground for complaint or any fault, because he was faithful, and no error or fault was found in him. Then these men said, "We shall not find any ground for complaint against this Daniel unless we find it in connection with the law of his God."
Then these presidents and satraps came by agreement to the king and said to him, "O King Darius, live for ever! All the presidents of the kingdom, the prefects and the satraps, the counsellors and the governors are agreed that the king should establish an ordinance and enforce an interdict, that whoever makes petition to any god or man for thirty days, except to you, O king, shall be cast into the den of lions. Now, O king, establish the interdict and sign the document, so that it cannot be changed, according to the law of the Medes and the Persians, which cannot be revoked." Therefore King Darius signed the document and interdict.
When Daniel knew that the document had been signed, he went to his house where he had windows in his upper chamber opened toward Jerusalem; and he got down upon his knees three times a day and prayed and gave thanks before his God, as he had done previously. Then these men came by agreement and found Daniel making petition and supplication before his God. They they came near and said before the king, concerning the interdict, "O king! Did you not sign an interdict, that any man who makes petition to any god or man within thirty days except to you, O king, shall be cast into the den of lions?" The king answered, "The thing stands fast, according to the law of the Medes and Persians, which cannot be revoked." Then they answered before the king, "That Daniel, who is one of the exiles from Judah, pays no heed to you, O king, or the interdict you have signed, but makes the petition three times a day."
Then the king, when he heard these words, was much distressed, and set his mind to deliver Daniel; and he laboured till the sun went down to rescue him. Then these men came by agreement to the king, and said to the king, "Know, O king, that it is a law of the Medes and Persians that no interdict or ordinance which the king established can be changed."
Then the king commanded, and Daniel was brought and cast into the den of lions. ....
(Note : LORD GOD intervened in this matter, and the lions did not eat Daniel. But it can be seen that many Laws which are passed serve an ulterior purpose.)