What does Daniel 6:21 mean?

Then the king went to his palace, and passed the night fasting. No musical instruments were brought before him; and his sleep fled from him.

Then the king arose very early in the morning, and went in haste to the den of lions.

When he came near to the den to Daniel, he cried with a troubled voice. The king spoke and said to Daniel, “Daniel, servant of the living God, is your God, whom you serve continually, able to deliver you from the lions?”

My God has sent his angel, and has shut the lions’ mouths, and they have not hurt me; because as before him innocence was found in me; and also before you, O king, I have done no harm.”

Then the king was exceedingly glad, and commanded that they should take Daniel up out of the den. So Daniel was taken up out of the den, and no kind of harm was found on him, because he had trusted in his God.

The king commanded, and they brought those men who had accused Daniel, and they cast them into the den of lions, them, their children, and their wives; and the lions mauled them, and broke all their bones in pieces, before they came to the bottom of the den.