What does Daniel 3:24 mean?
The "furnace" in this incident was probably a lime kiln with an opening near the bottom used to remove waste and ashes as well as to allow air to flow through the fire. Nebuchadnezzar has acted with intense rage at being defied (Daniel 3:16–18), commanding a series of foolish steps (Daniel 3:19–23) to demonstrate his power over these Hebrew men (Daniel 1:6–7). As part of his spite, the king seems to have taken a seat where he could watch his victims burn, likely through the opening in the side of the furnace.What he sees causes the king to stand up in shock. His comments are something like asking, "am I seeing things? Do you see what I see?" Certainly, God intended the king to see the miracle being performed in the fire. What Nebuchadnezzar witnesses proves God's power is far beyond that of any earthly ruler (Daniel 3:15). The advisors confirm that only three men fell into the fire—the unfortunate executioners probably died on top of the furnace trying to push the Hebrews into the hole (Daniel 3:22). Yet the king will claim he sees four people, who are not only alive, but unrestrained and moving.
The king will refer to one of these four figures as resembling "a son of the gods" (Daniel 3:25) and later as an "angel" or "messenger" of the God of the Israelite men (Daniel 3:28).