Then Nebuchadnezzar spake, and said, Blessed be the God of Shadrach, Meshach, and Abednego, who hath sent his angel, and delivered his servants that trusted in him, and have changed the king's word, and yielded their bodies, that they might not serve nor worship any god, except their own God.
Then Nebuchadnezzar ... said, Blessed be the God of Shadrach. In giving some better traits in Nebuchadnezzar's character, Daniel agrees with Jeremiah 39:11-12, "Now Nebuchadrezzar ... gave charge concerning Jeremiah to Nebuzaradan the captain of the guard, saying, Take him, and look well to him, and do him no harm; but do unto him even as he shall say unto thee;" Jeremiah 42:12.
And have changed the king's word - have made the king's attempt to coerce into obedience vain. Have set aside my word (so "alter this word," means set aside my commandment, Ezra 6:11) from regard to God. Nebuchadnezzar now admits that God's law should be obeyed rather than his (Acts 5:29, "We ought to obey God rather than men").
Yielded their bodies - namely, to the fire, as a voluntary offering, in testimony of their faithfulness to God (cf. Romans 12:1, "I beseech you ... by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service").
That they might not serve - by sacrificing.
Nor worship any god - by prostration of the body. Decision for God at last gains the respect even of the worldly (Proverbs 16:7).