Daniel’s Chapter 3 and 4 use Nebuchadnezzar, king of Babylonia, as a metaphorical representation of the whole giant image of four world empires in order to unveil the nature and problems associated with the whole world’s temporal-power structure.
The focus of his Chapter 3 is the intolerance of temporal power for religious freedom, the idea that all peoples must adopt and follow the deific concept of any mortal ruler or else suffer the consequences. This is one of the chief evils for millennia. It is based on forced adoption instead of on following a loving exemplar. It is based on the idea that a mortal ruler can be omniscient and that the governed are too ignorant to make an intelligent and conscientious deific decision.
The key to understanding this third chapter of Daniel is recognizing this chapter as a prophecy that, with unbridled, human temporal power, come religious intolerance and persecution. Thus, beware the giant image of gold, of silver, of brass, of iron. As Daniel also illustrates, the courage of the faithful exposes the evil of such power.