Idol worship had come to the children of Israel, and they were singing and dancing to celebrate their devotion to the golden calf. Worshipping Nebuchadnezzar's statue Hananiah, Azariah, and Mishael were part of the crowd required to attend the unveiling of the new statue of Nebuchadnezzar. They were instructed to bow down as soon as they heard the instruments play. Music was a call to worship. They refused to obey the call of the music, even though they knew it could cost them their lives.
Music is a reflection of the heart.
How much better it is to have a wise man point out our errors than to listen to the advice of foolish men presented in a song with a catchy tune. This is certainly an apt description of most of the music broadcast over the airwaves today.