biblewise
Chapter 6, verse 12
Then 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 god 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.