Daniel 6:12-15

Then they came near and said before the king, concerning the injunction, “O king! Did you not sign an injunction, that anyone 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 and said, “The thing stands fast, according to the law of the Medes and Persians, which cannot be revoked.” Then they answered and said before the king, “Daniel, who is one of the exiles from Judah, pays no attention to you, O king, or the injunction you have signed, but makes his 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 labored 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 injunction or ordinance that the king establishes can be changed.”