What does Daniel 3:21 mean?
King Nebuchadnezzar once promoted these men to high office (Daniel 2:48–49). Bitter rivals accused them of disobeying the king's command (Daniel 3:8, 12). The three Hebrews openly refused to worship an idol (Daniel 3:16–18). In a fit of temper, the king ordered some of his soldiers to tie the Jews up and throw them into a superheated furnace (Daniel 3:19–20).The clothing described would have been typical of Babylon in that era. Terms may vary, but the three Hebrews were likely wearing an undergarment, overgarment, and possibly ceremonial clothing. Execution victims would probably be stripped, in most cases, but here the king wants them executed instantly. None of this was necessary, but it all suited the king's intense rage at being defied.
God will thwart every detail of this temper tantrum. The men will survive (Daniel 3:26) without even their clothes smelling like smoke (Daniel 3:27), though their restraints will be dissolved (Daniel 3:25). Only the king's soldiers will be killed (Daniel 3:22).
Nearly the same information will be repeated (Daniel 3:23), as part of a pattern in this chapter. This segment repeats certain phrases and ideas, both for emphasis and as a way of satirizing the bureaucracy and control of Nebuchadnezzar's Babylon.