How did that heathen king know what the Son of God was like? The Hebrew captives filling positions of trust in Babylon had in life and character represented before him the truth. When asked for a reason of their faith, they had given it without hesitation. Plainly and simply they had presented the principles of righteousness, thus teaching those around them of God whom they worshiped. They had told of Christ, the Redeemer to come; and in the form of the fourth in the midst of the fire the king recognized the Son of God....
Then Shadrach, Meshach, and Abednego came forth before the vast multitude, showing themselves unhurt. The presence of their Saviour had guarded them from harm, and only their fetters had been burned. “And the princes, governors, and captains, and the king’s counsellors, being gathered together, saw these men, upon whose bodies the fire had no power, nor was an hair of their head singed, neither were their coats changed, nor the smell of fire had passed on them.” ...
The experiences of that day led Nebuchadnezzar to issue a decree, “That every people, nation, and language, which speak any thing amiss against the God of Shadrach, Meshach, and Abednego, shall be cut in pieces, and their houses shall be made a dunghill.” “There is no other God,” he urged as the reason for the decree, “that can deliver after this sort.”
In these and like words the king of Babylon endeavored to spread abroad before all the peoples of earth his conviction that the power and authority of the God of the Hebrews was worthy of supreme adoration. And God was pleased with the effort of the king to show Him reverence, and to make the royal confession of allegiance as widespread as was the Babylonian realm.
It was right for the king to make public confession, and to seek to exalt the God of heaven above all other gods; but in endeavoring to force his subjects to make a similar confession of faith and to show similar reverence, Nebuchadnezzar was exceeding his right as a temporal sovereign. He had no more right, either civil or moral, to threaten men with death for not worshiping God, than he had to make a decree consigning to the flames all who refused to worship the golden image. God never compels the obedience of man. He leaves all free to choose whom they will serve.—Prophets and Kings, 509-511. RC 89
“Thine, O Lord, is the greatness, and the power, and the glory, and the victory, and the majesty: for all that is in the heaven and in the earth is Thine.... In Thine hand is power and might; and in Thine hand it is to make great, and to give strength unto all.” (1 Chronicles 29:11, 12). Pr 303
"Then Nebuchadnezzar came near to the mouth of the burning fiery furnace, and spake , and said , Shadrach, Meshach, and Abednego, ye servants of the most high God, come forth , and come hither. Then Shadrach, Meshach, and Abednego, came forth of the midst of the fire." Daniel 3:26 (King James Version)