Daniel 6:12-15

12Then they came near, and spoke before the king concerning the king's decree: Hast thou not signed a decree, that every man that shall ask [anything] of any 1god or man within thirty days, except of thee, O king, shall be cast into the den of lions? The king answered and said, The thing is true, according to the law of the Medes and Persians, which may not be revoked.

13Then they answered and said before the king, That Daniel, who is of the children of the captivity of Judah, regardeth not thee, O king, nor the decree that thou hast signed, but maketh his petition three times a day.

14Then the king, when he heard these words, was sore distressed thereby, and set his heart on Daniel to save him; and he laboured till the going down of the sun to deliver him.

15Then these men came in a body unto the king, 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.