Daniel 6:16 (KJV)

Then the king, when he heard these words, was sore displeased with himself, and set his heart on Daniel to deliver him: and he laboured till the going down of the sun to deliver him.

Then these men assembled 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.

Then the king commanded, and they brought Daniel, and cast him into the den of lions. Now the king spake and said unto Daniel, Thy God whom thou servest continually, he will deliver thee.

And a stone was brought, and laid upon the mouth of the den; and the king sealed it with his own signet, and with the signet of his lords; that the purpose might not be changed concerning Daniel.

Then the king went to his palace, and passed the night fasting: neither were instruments of musick brought before him: and his sleep went from him.