Daniel 3:19,20

‘Then was Nebuchadnezzar full of fury, and the look on his face was changed against Shadrach, Meshach and Abednego. He spoke and commanded that they should heat the furnace seven times more than it was normally heated. And he commanded certain mighty men who were in his army to bind Shadrach, Meshach and Abednego, and to cast them into the burning, fiery furnace.'

Nebuchadnezzar had been well intentioned towards them, as the look on his face had revealed, but now at their refusal his fury knew no bounds. The look on his face changed. How dare these men defy him to his face? He had never experienced such treatment in all his days.

And yet within his heart there was a doubt. The quiet confidence of these men shook him. And the thought of their God disturbed him. Perhaps He might deliver them? So he took precautions. He had the furnace heated to the maximum possible, hotter than it had ever been before. ‘Seven times' may mean ‘to its ultimate', or it may be intended to suggest the divine perfection of the judgment from his god that would come on them. The use of the number may have indicated that by his action he was calling for help from his god against this other powerful God.

And he called for the mightiest men of his army. He wanted help from both god and man. He would see what their God could do against these combined forces. And then he had them bound and commanded that they be thrown into the intense heat of the overheated furnaces. He was satisfied that he had taken all possible precautions.

Once again we see that excessive intensity which would later come out in his mental illness, signs that indicated that all was not quite right in his mental state.